Over the last few working days, I spent a quite a bit of time playing around with XML. While searching through the net, I found few comprehensive PHP XML guides. There never was a ’1 stop all operations’ guide for learning XML.
As such I decided to club together examples of all kinds of operations I ever did on XML in a single post. I hope it benefits others out there who wish to learn more about XML manipulation.
Note : Since the post got quite large, I decided to only use the Tree Map style parsers – DOM & Simple XML.
Operations Performed:
(1) Create XML OR Array to XML Conversion OR CDATA Element Eg
(2) Edit XML – Edit/Modify Element Data (accessed serially)
(3) Edit XML – Edit specific Elements (accessed conditionally)
(4) Edit XML – Element Addition (to queue end)
(5) Edit XML – Element Addition (to queue start)
(6) Edit XML – Element Addition (before a specific node)
(7) Delete Elements (accessed serially)
(8) Delete Elements (accessed conditionally)
(9) Rearrange / Reorder Elements
(10) Display Required data in XML Form itself OR Remove all children nodes save one OR Copy/Clone Node Eg OR Compare/Search non numeric data (like date or time) to get result.
library.xml will be used in all operations.
ps : I have added the indention & spaces outside the tags in the below xml for a presentable xml form.
Remove them before saving your xml file else most of the usual XML functions wont work in the desired manner.
#######################################
// (3) Edit XML – Edit specific Elements (accessed conditionally)
#######################################
// (i) SimpleXML :
1
//Edit Title of book with author J.R.R.Tolkein
2
function fnSimpleXMLEditElementCond()
3
{
4
$library = new SimpleXMLElement('library.xml',null,true);
5
$book = $library->xpath('/library/book[author="J.R.R.Tolkein"]');
6
$book[0]->title .= ' Series';
7
header("Content-type: text/xml");
8
echo $library->asXML();
9
}
// (ii) DOM (with XPath):
01
//Edit Title of book with author J.R.R.Tolkein
02
function fnDOMEditElementCond()
03
{
04
$dom = new DOMDocument();
05
$dom->load('library.xml');
06
$library = $dom->documentElement;
07
$xpath = new DOMXPath($dom);
08
$result = $xpath->query('/library/book[author="J.R.R.Tolkein"]/title');
09
$result->item(0)->nodeValue .= ' Series';
10
// This will remove the CDATA property of the element.
11
//To retain it, delete this element (see delete eg) & recreate it with CDATA (see create xml eg).
12
#######################################
// (4) Edit XML – Element Addition (to queue end)
#######################################
// (i) SimpleXML :
01
//Add another Book to the end
02
function fnSimpleXMLAddElement2End()
03
{
04
$library = new SimpleXMLElement('library.xml',null,true);
05
$book = $library->addChild('book');
06
$book->addAttribute('isbn', '1004');
07
$book->addAttribute('pubdate', '1960-07-11');
08
$book->addChild('title', "To Kill a Mockingbird");
09
$book->addChild('author', "Harper Lee");
10
$book->addChild('price', "100");
11
header("Content-type: text/xml");
12
echo $library->asXML();
13
}
// (ii) DOM :
01
//Add another Book to the end
02
function fnDOMAddElement2End()
03
{
04
$dom = new DOMDocument();
05
$dom->load('library.xml');
06
$library = $dom->documentElement;
07
#######################################
//(5) Edit XML – Element Addition (to queue start)
#######################################
// (i) SimpleXML :
01
// Add a Book to List Start
02
// Insert Before Functionality not present in SimpleXML
03
// We can integrate DOM with SimpleXML to do it.
04
function fnSimpleXMLAddElement2Start()
05
{
06
$libSimple = new SimpleXMLElement('library.xml',null,true);
07
$libDom = dom_import_simplexml($libSimple);
08
09
$dom = new DOMDocument();
10
//returns a copy of the node to import
11
$libDom = $dom->importNode($libDom, true);
12
//associate it with the current document.
13
$dom->appendChild($libDom);
14
15
fnDOMAddElement2Start($dom); //see below DOM function
16
}
#######################################
// (6) Edit XML – Element Addition (before a specific node)
#######################################
// (i) SimpleXML :
01
// Add a Book Before attribute isbn 1002
02
// Insert Before Functionality not present in SimpleXML
03
// We can integrate DOM with SimpleXML to do it.
04
function fnSimpleXMLAddElementCond()
05
{
06
$libSimple = new SimpleXMLElement('library.xml',null,true);
07
$libDom = dom_import_simplexml($libSimple);
08
09
$dom = new DOMDocument();
10
//returns a copy of the node to import
11
$libDom = $dom->importNode($libDom, true);
12
//associate it with the current document.
13
$dom->appendChild($libDom);
14
15
fnDOMAddElementCond($dom); //see below DOM eg.
16
}
// (ii) DOM :
01
// Add a Book Before isbn 1002
02
function fnDOMAddElementCond($dom='')
03
{
04
if(!$dom)
05
{
06
$dom = new DOMDocument();
07
$dom->load('library.xml');
08
}
09
$library = $dom->documentElement;
10
#######################################
// (8) Delete Elements (accessed conditionally)
#######################################
// (i) SimpleXML :
01
// Delete a book with 20002
// Not possible to delete node found via XPath in SimpleXML. See below.
03
function fnSimpleXMLDeleteCond()
04
{
05
$library = new SimpleXMLElement('library.xml',null,true);
06
$book = $library->xpath('/library/book[price>"200" and price<"500"]');
07
08
//Problem here....not able to delete parent node using unset($book[0]);
09
// unset of parent node only works when accessing serially. eg : unset($library->book[0]);
10
01
// Delete the book with 20002
function fnDOMDeleteCond()
03
{
04
$dom = new DOMDocument();
05
$dom->load('library.xml');
06
$library = $dom->documentElement;
07
$xpath = new DOMXPath($dom);
08
$result = $xpath->query('/library/book[price>"200" and price<"500"]');
09
$result->item(0)->parentNode->removeChild($result->item(0));
10
header("Content-type: text/xml");
11
echo $dom->saveXML();
12
}
#######################################
// (9) Rearrange / Reorder Elements
#######################################
// (i) SimpleXML :
01
// Exchange Position of 2nd book with 3rd : fnSimpleXMLRearrange(2,3);
02
// Due to absence of an inbuilt function (DOM has it), we have to make our own function in SimpleXML.
03
//Better to use DOM.
04
function fnSimpleXMLRearrange($num1,$num2)
05
{
06
$libSimple= new SimpleXMLElement('library.xml',null,true);
07
//$library->book[3] = $library->book[0]; // this doesnt work
08
09
$libDom = dom_import_simplexml($libSimple);
10
11
$dom = new DOMDocument();
12
//returns a copy of the node to import
13
$libDom = $dom->importNode($libDom, true);
14
//associate it with the current document.
15
$dom->appendChild($libDom);
16
fnDOMRearrange($num1,$num2,$dom); // see below DOM function
17
}
// (ii) DOM :
01
// Exchange Position of 2nd book with 3rd : fnDOMRearrange(2,3);
02
function fnDOMRearrange($num1,$num2,$dom=0)
03
{
04
if(!$dom)
05
{
06
$dom = new DOMDocument();
07
$dom->load('library.xml');
08
}
09
$dom = new DOMDocument();
10
$dom->load('library.xml');
11
$library = $dom->documentElement;
12
17
$num1 = fnDOMConvIndex($num1);
18
$num2 = fnDOMConvIndex($num2);
19
$library->childNodes->item(0)->parentNode->insertBefore($library->childNodes->item($num2),$library->childNodes->item($num1));
20
header("Content-type: text/xml");
21
echo $dom->saveXML();
22
}
23
function fnDOMConvIndex($num)
24
{
25
$num = ($num==1)?$num:$num+1;//If its 1 then do nothing.
26
$num = ($num%2)?$num:$num+1; //Always odd index due to nature of DOM Element Index.
27
return $num;
28
}
#######################################
// (10) Display Required data in XML Form itself OR
Remove all children nodes save one OR
Copy/Clone Node Eg OR
Compare/Search non numeric data (like date or time) to get result.
#######################################
// (i) SimpleXML :
1
// Display Books published after 1980 in XML Form itself.
2
// No function to copy node directly in SimpleXML.
3
// Its simpler for this functionality to be implemented in DOM.
4
function fnSimpleXMLDisplayElementCond()
5
{
6
$library = new SimpleXMLElement('library.xml',null,true);
7
$book = $library->xpath('/library/book[translate(@pubdate,"-","")>translate("1980-01-01","-","")]');
8
// Manually create a new structure then add searched data to it (see create xml eg.)
9
}
// (ii) DOM :
01
// Display Books published after 1980 in XML Form itself.
02
function fnDOMDisplayElementCond()
03
{
04
$dom = new DOMDocument();
05
$dom->load('library.xml');
06
$library = $dom->documentElement;
07
$xpath = new DOMXPath($dom);
08
09
// Comparing non numeric standard data
10
$result = $xpath->query('/library/book[translate(@pubdate,"-","")>translate("1980-01-01","-","")]');
11
// For simpler search paramater use this :
12
//$result = $xpath->query('/library/book[author="J.R.R.Tolkein"]');
13
14
// Copy only node & its attributes not its contents.
15
$library = $library->cloneNode(false);
16
// Add the 1 element which is search result.
17
$library->appendChild($result->item(0));
18
19
header("Content-type: text/xml");
20
echo $dom->saveXML($library);
21
}
Lessons Learn’t :
SimpleXML is fantastic for those who will only briefly flirt with XML (or beginners) & perform simple operations on XML.
DOM is an absolute necessity for performing complex operations on XML data. Its learning curve is higher than SimpleXML off course but once you get the hang of it , you will know its very logical.
Use XPath for conditional access to data. For serial access (like last book) XPath is not needed (but u can use it) since I can use normal DOM / SimpleXML node access.
I have used PHPUnit heavily now for the last 4 years. As anyone that is heavily involved in writing Unit Tests knows, test doubles (commonly referred to as mock objects) are a necessary part of your toolbox. The mocking options that we used to have for PHP unit testing have traditionally been fairly limited and most all of them in some form or another were ports of JMock. The way PHP operates as well as some decisions made to more closely emulate how JMock does things lead to functionality in the existing mock library for PHPUnit that for some are a hassle. This ranges from PHPUnit implicitly calling the “mockee’s” constructor (you have to explicitly specify that you do not want to call the constructor) to the pain of trying to stub or verify multiple invocations of the same method with different parameters.
Over the last three years, my experience as well as the musing of some of my colleagues has led me to believe that a lot of what I don’t like about mocking in php is the result of the fundamental notions of combining stubbing with verification and setting expectations ahead of method calls instead of verifying that what you expected to happen has indeed happened. This was essentially proven to me over the last year and a half as I have been heavily working with Java code and as a result have been using the Mockito mocking library for Java. The result of this work is the Phake Mocking Framework.
Now I am fairly certain that at least 5 or 6 people (which may constitute everyone who reads this) are rolling their eyes by now. So instead of going further into why I like this style of mocking I’ll just show you how to use it. Phake was designed with PHPUnit in mind, however I don’t really see any reason why it couldn’t be used in other testing frameworks as well. It is on my roadmap to confirm support for other frameworks. In any case, I will be using PHPUnit for my examples.
This document assumes you already have a good understanding of the basics of mocking. If the terms ‘Mocking’, ‘Stubbing’, and ‘Test Doubles’ mean nothing to you, I would recommend checking out the following links:
PHPUnit on Mock Objects Wikipedia on Mock Objects The Universe on Mock Objects Getting Started
You can get a copy of Phake from Github. If you are familiar and comfortable with with git you can just clone my repository. If you would rather avoid the trappings of Github, you can also download Phake’s latest release tarball. Either way will result in a directory with two subdirectories: src and test. You will want to move the contents of the src directory to somewhere in your include path (such as /usr/share/php). Once you have done this, you can simply include “Phake.php” in any of your tests or in your bootstrap script and you will be off to the races.
UPDATE!!!
I just set up a pear channel to distribute phake as well. So if you would like to install Phake using pear, just do the following:
pear channel-discover pear.digitalsandwich.com pear install channel://pear.digitalsandwich.com/Phake-1.0.0alpha To show you some of the basics of how to use this framework, I am going to write various bits of codes to mock, verify, stub, etc the following class:
class MyClass { private $value;
public function __construct($value) { $this->value = $value; }
public function getValue() { return $this->value; }
public function subtract($int) { return $this->value - $int; } }
?> Stubbing
require_once 'Phake.php'; class Test extends PHPUnit_Framework_TestCase { public function testStubbingGetValue() { // Sets up the mock object. // Analogous to $this->getMock() in PHPUnit $mock = Phake::mock('MyClass');
// Builds the stub for getValue. // Essentially any call to getValue will return 42 Phake::when($mock)->getValue()->thenReturn(42);
$this->assertEquals(42, $mock->getValue()); } } You can also do conditional stubbing based on passed in parameters.
public function testStubbingGetValue2() { $mock = Phake::mock('MyClass');
// You can pass parameters into the stubbed method to indicate you // only want to stub matching invocations. By default, anything // passed in must be loosely matched ('==') Phake::when($mock)->subtract(42)->thenReturn(30);
$this->assertEquals(30, $mock->subtract(42));
// It is important to note that any unstubbed calls will return null. // Since 41 != 42 this call will return null. $this->assertNull($mock->subtract(41)); } If a specific invocation or call of a mock object has not been stubbed, it will return null. This behavior is different than the default behavior of PHPUnit’s mocking framework. If you need the default PHPUnit behavior then you could use something called partial mocks. Partial mocks are setup to call the constructor of the class being mocked and for any call that has not been stubbed, the parent method will be called.
public function testStubbingGetValue3() { // Creates a mock object whose constructor will call // MyClass::__construct(42); $mock = Phake::partMock('MyClass', 42);
Phake::when($mock)->subtract(42)->thenReturn(0);
// Since 18 != 42, the real method gets call $this->assertEquals(24, $mock->subtract(18)); } You can also specify on a per call basis that you want to call the parent, using the thenCallParent() method instead of thenReturn(). The different values you can use for stubbing are referred to as ‘Answers’. Here are a list of them and what they will do when a matching invocation is called:
thenReturn(mixed $var) – Will return the exact value passed in. thenCallParent() – Will return the results of calling the mocked parent method. thenThrow(Exception $e) – Will throw $e. captureReturnTo(&$variable) – Acts exactly like thenCallParent() however it also captures the value that the parent returned to $variable. This allows you to run assertions. This comes in very handy for testing legacy code with protected or private factory methods whose return values are never returned out of the tested method’s scope. The other thing to take note of stubbing is that any PHPUnit constraints are supported.
public function testStubbingGetValue4() { $mock = Phake::mock('MyClass');
//Matches any call to subtract() where the passed in value equals 42 Phake::when($mock)->subtract(42)->thenReturn(30);
//Matches any call to subtract() where the passed in value is less // than 42. Notice that this is a phpunit constraint Phake::when($mock)->subtract($this->lessThan(42))->thenReturn(29);
$this->assertEquals(30, $mock->subtract(42)); $this->assertEquals(29, $mock->subtract(41)); } This gives you the same kind of stubbing flexibility that you have present in PHPUnit.
Verification
Verifying that methods on your stub are called is starkly different then how it is done in PHPUnit. The most apparent symptom of this difference is that you verify calls after the calls to your test methods have been made.
public function testVerify1() { // You can apply stubbings and verifications to the same mock objects $mock = Phake::mock('MyClass');
$mock->getValue();
//Notice, getValue() has already been called Phake::verify($mock)->getValue(); } You of course have the same matching functionality at your disposal.
public function testVerify2() { $mock = Phake::mock('MyClass');
$mock->subtract(40);
//Notice the constraint Phake::verify($mock)->subtract($this->lessThan(42)); } By default, verify only allows a single matching invocation. You can also specify that a specific number of invocations should be allowed.
public function testVerify3() { $mock = Phake::mock('MyClass');
$mock->subtract(40); $mock->subtract(39);
//The number of times is passed as the second parameter of //Phake::verify() Phake::verify($mock, Phake::times(2))->subtract($this->lessThan(42)); } You can also use Phake::atLeast($n) and Phake::atMost($n) instead of Phake::times($n).
You can also specify that you don’t expect there to be any interactions with a mock.
public function testVerify4() { $mock = Phake::mock('MyClass');
// This will ensure that UP TO THIS POINT no methods on $mock have // been called Phake::verifyNoInteraction($mock);
// This would not result in an error, this can be prevented with // another method explained below $mock->getValue();
} I am sure you noticed the comment that Phake::verifyNoInteraction() only verifies that no calls were made up to that point. You can essentially freeze a mock with another method
public function testVerify5() { $mock = Phake::mock('MyClass');
$mock->getValue();
// This will ensure that no methods on $mock will be called after this // point Phake::verifyNoFurtherInteraction($mock); } There are a few more advanced things you can do with something called argument captors.
public function testVerify6() { $mock = Phake::mock('MyClass');
$mock->subtract(42);
// Phake::capture tells Phake to store the parameter passed to // subtract as the variable $val Phake::verify($mock)->subtract(Phake::capture($val));
$this->assertEquals(42, $val); } This is a very pedestrian example, but it is not that uncommon for fairly complicated objects to passed in and out of methods. Argument capturing allows you to much more succinctly assert the state of those types of parameters. It is definitely overkill for asserting scalar types or simple objects.
More to Come
This really does cover the very basics of the Phake framework. In the coming days I will be putting out smaller more focused articles discussing some of the specific functionality. In the meantime I would love to get some feedback from anyone who is brave enough to play with this. My future roadmap basically involves shoring up the current code base a little bit more, adding a few pieces of missing or suboptimal functionality (I’m not so sure I have implemented ‘consecutive calls’) but I anticipate releasing an RC version no later than the end of January. Also, I am currently using and monitoring the issue tracker for Phake at github, so if you have some functionality you would like or find any bugs in your exploring, you can also open an issue there. Also, if you would like to help out with contributions, they are certainly welcome.
This document contains guidelines for web applications built by the Creative Technology (front end engineering) practice of Isobar US. It is to be readily available to anyone who wishes to check the iterative progress of our best practices. If you have any feedback, please leave a comment on the announcement blog post.
This document's primary motivation is two- fold: 1) code consistency and 2) best practices. By maintaining consistency in coding styles and conventions, we can ease the burden of legacy code maintenance, and mitigate risk of breakage in the future. By adhering to best practices, we ensure optimized page loading, performance and maintainable code.
General Guidelines◊Back to Top
Pillars of Front-end Development◊
Separation of presentation, content, and behavior.
Markup should be well-formed, semantically correct and generally valid.
Javascript should progressively enhance the experience.
General Practices◊
Indentation◊
For all code languages, we require indentation to be done via soft tabs (using the space character). Hitting Tab in your text editor shall be equivalent to four spaces.
Readability vs Compression◊
We prefer readability over file-size savings when it comes to maintaining existing files. Plenty of whitespace is encouraged, along with ASCII art, where appropriate. There is no need for any developer to purposefully compress HTML or CSS, nor obfuscate JavaScript.
We will use server-side or build processes to automatically minify and gzip all static client-side files, such as CSS and JavaScript.
Markup◊Back to Top
The first component of any web page is the tag-based markup language of HTML. The Hyper Text Markup Language (HTML) has a sordid history but has come into its own in the last few years. After a lengthy experimentation with the XML-based XHTML variant the industry has accepted that HTML is the future of the web.
Markup defines the structure and outline of a document and offers a structured content. Markup is not intended to define the look and feel of the content on the page beyond rudimentary concepts such as headers, paragraphs, and lists. The presentation attributes of HTML have all been deprecated and style should be contained in style sheets.
HTML5◊
HTML5 is a new version of HTML and XHTML. The HTML5 draft specification defines a single language that can be written in HTML and XML. It attempts to solve issues found in previous iterations of HTML and addresses the needs of web Applications, an area previously not adequately covered by HTML. (source).
We will use the HTML5 Doctype and HTML5 features when appropriate.
We will test our markup against the W3C validator, to ensure that the markup is well formed. 100% valid code is not a goal, but validation certainly helps to write more maintainable sites as well as debugging code. Isobar does not guarantee code is 100% valid, but instead assures the cross-browser experience is fairly consistent.
Template◊
For HTML5 Documents we use a fork of H5BP modified for our own project needs. Fork the Github repository.
Doctype◊
A proper Doctype which triggers standards mode in your browser should always be used. Quirks mode should always be avoided.
A nice aspect of HTML5 is that it streamlines the amount of code that is required. Meaningless attributes have been dropped, and the DOCTYPE declaration has been simplified significantly. Additionally, there is no need to use CDATA to escape inline JavaScript, formerly a requirement to meet XML strictness in XHTML.
HTML5 Doctype
1.
Character Encoding◊
All markup should be delivered as UTF-8, as its the most friendly for internationalization. It should be designated in both the HTTP header and the head of the document.
Setting the character set using tags.
1.
In HTML5, just do:
1.
General Markup Guidelines◊
The following are general guidelines for structuring your HTML markup. Authors are reminded to always use markup which represents the semantics of the content in the document being created.
Use actual P elements for paragraph delimiters as opposed to multiple BR tags.
Make use of DL (definition lists) and BLOCKQUOTE, when appropriate.
Items in list form should always be housed in a UL, OL, or DL, never a set of DIVs or Ps.
Use label fields to label each form field, the for attribute should associate itself with the input field, so users can click the labels. cursor:pointer; on the label is wise, as well. note 1 note 2
Do not use the size attribute on your input fields. The size attribute is relative to the font-size of the text inside the input. Instead use css width.
Place an html comment on some closing div tags to indicate what element you're closing. It will help when there is lots of nesting and indentation.
Tables shouldn't be used for page layout.
Use microformats and/or Microdata where appropriate, specifically hCard and adr.
Make use of THEAD, TBODY, and TH tags (and Scope attribute) when appropriate.
Table markup with proper syntax (THEAD,TBODY,TH [scope])
01.
02.
03.
04.
05.
06.
07.
08.
09.
10.
11.
12.
13.
14.
Table header 1
Table header 2
Table data 1
Table data 2
Always use title-case for headers and titles. Do not use all caps or all lowercase titles in markup, instead apply the CSS property text-transform:uppercase/lowercase.
Quoting Attributes◊
While the HTML5 specification defines quotes around attributes as optional for consistency with attributes that accept whitespace, all attributes should be quoted.
1.
This is my paragraph of special text.
CSS◊Back to Top
The second component of a web page is the presentation information contained in the Cascading Style Sheet (CSS.) Web browsers successful implementation of CSS has given a whole generation of web authors site-wide control over the look and feel of their web sites.
Just as the information on a web page is semantically described in the HTML Markup, CSS describes all presentation aspects of the page via a description of it's visual properties. CSS is powerful in that these properties are mixed and matched via identifiers to control the page's layout and visual characteristics through the layering of style rules (the "cascade").
General Coding Principles◊
Add CSS through external files, minimizing the # of files, if possible. It should always be in the HEAD of the document.
Use the LINK tag to include, never the @import.
Including a stylesheet
1.
Don't use inline styling
1.
This is poor form, I say
Don't include styles inline in the document, either in a style tag or on the elements. It's harder to track down style rules.
Use a reset CSS file (like the one present in H5BP or the Eric Meyers reset) to zero our cross-browser weirdness.
Use a font-normalization file like YUI fonts.css
Elements that occur only once inside a document should use IDs, otherwise, use classes.
Understand cascading and selector specificity so you can write very terse and effective code.
Write selectors that are optimized for speed. Where possible, avoid expensive CSS selectors. For example, avoid the * wildcard selector and don't qualify ID selectors (e.g. div#myid) or class selectors (e.g. table.results.) This is especially important with web applications where speed is paramount and there can be thousands or even tens of thousands of DOM elements. More on writing efficient CSS on the MDC.
CSS Box Model◊
Intimate knowledge and understanding of the CSS and browser-based box model is necessary for conquering the fundamentals of CSS layouts.
3D CSS Box Model diagram by Jon Hicks.
CSS Validation◊
We typically don't use the W3C validator.
CSS Formatting◊
At minimum, format CSS with selectors on one line and each property on its own line. The declarations are indented.
As an enhancement to that style, related or child styles and additional 2 or 4 spaces. That allows for hierarchical scanning and organization and makes (for some people) an easier-to-read style sheet.
01.
.post-list li a{
02.
color:#A8A8A8;
03.
}
04.
.post-list li a:hover{
05.
color:#000;
06.
text-decoration:none;
07.
}
08.
.post-list li .author a, .post-list li .author a:hover{
09.
color:#F30;
10.
text-transform:uppercase;
11.
}
For multiple author environments, single line CSS should be avoided because it can cause issues with version control.
Alphabetize◊
If you're performance obsessed alphabetizing CSS properties increases the odds of larger repeatable patterns being present to aid in GZIP compression.
Classes vs. IDs◊
You should only give elements an ID attribute if they are unique. They should be applied to that element only and nothing else. Classes can be applied to multiple elements that share the same style properties. Things that should look and work in the same way can have the same class name.
1.
2.
Category 1
3.
Category 2
4.
Category 3
5.
Naming Conventions for Selectors◊
It is always preferable to name something, be it an ID or a class, by the nature of what it is rather than by what it looks like. For instance, a class name of bigBlueText for a special note on a page is quite meaningless if it has been changed to have a small red text color. Using a more intelligent convention such as noteText is better because when the visual style changes it still makes sense.
Selectors◊
The CSS Selectors Level 3 specification introduces a whole new set of CSS Selectors that are extremely useful for better selection of elements.
Pseudo-classes◊
Pseudo-classes enable you to dynamically style content. Some pseudo-classes have existed since CSS1 (:visited, :hover, etc.) and CSS2 (:first-child, :lang). As of CSS3, 16 new pseudo-classes have been added to the list and are especially useful for styling dynamic content. Learn how to use pseudo-classes in-depth.
Combinators & Attribute Selectors◊
Combinators provide shortcuts for selecting elements that are a descendant element, a child element, or an element's sibling.
Attribute Selectors are great for finding elements that have a specific attribute and/or specific value. Knowledge of regular expressions helps with attribute selectors.
Specificity◊
Browsers calculate a selector's specificity to determine which CSS rule should apply. If two selectors apply to the same element, the one with the higher specificity wins.
IDs have a higher specificity than attribute selectors do, and class selectors have higher specificity than any number of element selectors. Always try to use IDs to increase the specificity. There are times when we may try to apply a CSS rule to an element and it does not work no matter what we try. This is likely because the specificity of the selector used is lower than another one and the properties of the higher one are taking precedence over those you want to apply. This is more common in working with larger more complex stylesheets. It isn't a big issue with smaller projects usually.
Calculating specifity◊
When working with a large and complex stylesheet it helps to know how to calculate the value of a selector's specificity, to save you time and to make your selectors more efficient.
Specificity is calculated by counting various components of your CSS and expressing them in a form (a,b,c,d).
Element, Pseudo Element: d = 1 – (0,0,0,1)
Class, Pseudo class, Attribute: c = 1 – (0,0,1,0)
Id: b = 1 – (0,1,0,0)
Inline Style: a = 1 – (1,0,0,0)
However, it may be better to use a specificity calculator.
Specificity Calculator
Some things you should know about specificity
IE Specificity bugs
Using !important overrides all specificity no matter how high it is. We like to avoid using it for this reason. Most of the time it is not necessary. Even if you need to override a selector in a stylesheet you don't have access to, there are usually ways to override it without using !important. Avoid using it if possible.
Pixels vs. Ems◊
We use the px unit of measurement to define font size, because it offers absolute control over text. We realize that using the em unit for font sizing used to be popular, to accommodate for Internet Explorer 6 not resizing pixel based text. However, all major browsers (including IE7 and IE8) now support text resizing of pixel units and/or full-page zooming. Since IE6 is largely considered deprecated, pixels sizing is preferred. Additionally, unit-less line-height is preferred because it does not inherit a percentage value of its parent element, but instead is based on a multiplier of the font-size.
Correct
1.
#selector {
2.
font-size: 13px;
3.
line-height: 1.5; /* 13 * 1.5 = 19.5 ~ Rounds to 20px. */
4.
}
Incorrect
1.
/* Equivalent to 13px font-size and 20px line-height, but only if the browser default text size is 16px. */
2.
#selector {
3.
font-size: 0.813em;
4.
line-height: 1.25em;
5.
}
Internet Explorer Bugs◊
Inevitably, when all other browsers appear to be working correctly, any and all versions of Internet Explorer will introduce a few nonsensical bugs, delaying time to deployment. While we encourage troubleshooting and building code that will work in all browsers without special modifications, sometimes it is necessary to use conditional if IE comments for CSS hooks we can use in our stylesheets. Read more on paulirish.com
Fixing IE
1.
2.
3.
4.
5.
1.
.box { float: left; margin-left: 20px; }
2.
.ie6 .box { margin-left: 10px; }
If you're using HTML5 (and the HTML5 Boilerplate) we encourage the use of the Modernizer JavaScript library and this pattern:
1.
2.
3.
4.
5.
Shorthand◊
In general, CSS shorthand is preferred because of its terseness, and the ability to later go back and add in values that are already present, such as the case with margin and padding. Developers should be aware of the TRBL acronym, denoting the order in which the sides of an element are defined, in a clock-wise manner: Top, Right, Bottom, Left. If bottom is undefined, it inherits its value from top. Likewise, if left is undefined, it inherits its value from right. If only the top value is defined, all sides inherit from that one declaration.
For more on reducing stylesheet code redundancy, and using CSS shorthand in general:
http://qrayg.com/journal/news/css-background-shorthand
http://sonspring.com/journal/css-redundancy
http://dustindiaz.com/css-shorthand
Images◊
For repeating images, use something larger than 1x1 pixels
You should never be using spacer images.
Use CSS sprites generously. They make hover states easy, improve page load time, and reduce carbon dioxide emissions.
Typically, all images should be sliced with a transparent background (PNG8). All should be cropped tightly to the image boundaries.
However, the logo should always have a background matte and have padding before the crop. (so other people can hotlink to the file)
General Text and Font Styling◊
Headings◊
Define default styling for h1-h6 headings including headings as links. It's helpful to declare these at the top of your CSS document, and modify them with as necessary for consistency across the site.
Headings should show a hierarchy indicating different levels of importance from the top down starting with h1 having the largest font size.
SEO: To get a rough idea of how your page hierarchy is organized and read, use your Developer Toolbar to disable CSS. You'll end up with a text-based view of all your h1-h6 tags, strong, em, etc.
Links◊
Default styles for links should be declared and different from the main text styling, and with differing styles for hover state.
When styling links with underlines use border-bottom and some padding with text-decoration: none;. This just looks better.
Web Typography◊
The use of custom fonts and typefaces on the web has been growing more popular the past few years. with native browser support on the rise and several supporting services and APIs now available there is real momentum in this space. Each of these approaches have their own pros and cons. Before a project kicks off it's best to do research into technology and licensing limitations to choose the proper approach for the specific project.
All of these approaches have drawbacks in code overhead, development time and performance (clock and perceived). Familiarizing yourself with these issues and communicating them to the other members of the team and to the client will save significant problems later on in the project.
Listed here are some popular methods of embed custom fonts, list in the order of our preference for implementation.
@font-face◊
The @font-face at-rule allows you to define custom fonts. It was first defined in the CSS2 specification, but was removed from CSS2.1. Currently, it's a draft recommendation for CSS3.
Our first and most preferred choice for customizing fonts on the web is @font-face, simply because it is part of the CSS Fonts Module working draft which means it will continue to grow in popularity as browser support grows, and ease of use for it improves as it becomes more stable.
For now, when using @font-face it's recommended to declare the source for each font format. This is important if you want it to work in the most number of browsers, though it is not a requirement for use.
The font formats included in the specification are:
woff: WOFF (Web Open Font Format)
ttf: TrueType
ttf, otf: OpenType
eot: Embedded OpenType
svg, svgz: SVG Font
Bulletproof @font-face◊
For full cross-browser compatibility use Fontsprings' new bulletproof @font-face syntax (latest version as of 2/21/11).
01.
@font-face {
02.
font-family: 'MyFontFamily';
03.
src: url('myfont-webfont.eot'); /* IE9 Compat Modes */
04.
src: url('myfont-webfont.eot?iefix') format('eot'), /* IE6-IE8 */
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url('myfont-webfont.woff') format('woff'), /* Modern Browsers */
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url('myfont-webfont.ttf') format('truetype'), /* Safari, Android, iOS */
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url('myfont-webfont.svg#svgFontName') format('svg'); /* Legacy iOS */
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font-weight: ;
09.
font-style: ;
10.
// etc.
11.
}
Here's a working demo using this version of implementation.
Prevent Compatibility Mode◊
Sometimes IE can have a mind of its own and will switch to compatibility mode without you knowing. Include the following in the site to prevent your site from defaulting to compatibility mode:
1.
Tips for @font-face◊
IE 6–8 will only accept a TrueType font packaged as an EOT.
font-weight and font-style have different meanings within @font-face. Declarations where font-weight:bold; means this is the bold version of this typeface, rather than apply bold to this text
@font-face gotchas
Pros
Easy to implement
Large variety of APIs
Customizable
Easy to add to elements
Nothing required besides CSS
Is currently part of the working draft of CSS Fonts Module 3
Cons
Limited browser support if used improperly
Some older versions of modern browsers (Chrome, Opera) don't always render well. Text can have rough edges. **I have not been able to confirm whether this is still an issue now or not.
Google WebFonts API & Font Loader◊
There are two options available with Google Webfonts. Both options have their downsides of course but they can be just as good to use as @font-face, it all depends on a projects needs.
Webfonts API◊
Google's Webfonts API essentially does the same thing as @font-face, it just does all the hard work for you, providing wider browser support.The major drawback to this method is the very small font library it uses. To make it work all you need to do is include the stylesheet + the font name.
1.
Then define a style for the selector you want to apply the font to:
1.
CSS selector {
2.
font-family: 'Font Name', serif;
3.
}
Webfont Loader◊
Another option Google offers is the Webfont Loader which is a JavaScript library that allows for more control than the font API does. You can also use multiple webfont providers like Typekit. To use it include the script in your page:
01.
Including the webfont.js file this way is faster if not already using the Ajax APIs. Otherwise you should use this:
1.
2.
By using the Webfont Loader you have more ability to customize things including the use of more fonts, not just those in the Google Webfont library which is not large. However, it then requires you to load JavaScript, sacrificing one thing for another.
Pros
Very easy to implement
Wide browser support
Can be combined with Typekit
Customizable when using the font loader
API does the same thing as @font-face
Cons
Very small font library if using the font API
Using the Webfont Loader requires the use of JavaScript to work
Most browsers will load the rest of the page first, leaving a blank space where the text would be, or otherwise show the fallback option if one exists, until the page fully loads.
Some fonts in the webfont library render poorly on Windows
Cufon◊
If you choose to use Cufon, it is highly recommended you use the Cufon compressed version. You will need to convert your font using the generator.
1.
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We recommend using Cufon sparingly since it can cause a lot of overhead if applied to a large amount of text. For more info visit the Cufon Wiki.
Pros
Wide browser support
Renders well in supported browsers
Customizable
Easy to implement
Cons
Requires use of JS to work
Text can't be selected that uses it
Not all characters can be used
Customization can be a pain
Not always easy to apply to multiple elements, especially when adding effects like hovers
Typekit◊
Using Typekit has its advantages and shouldn't be completely disregarded when choosing which method to use for adding custom fonts to a web site. It has strong platform integration and is a scalable and popular service. It can be used with Google Webfonts and is easily added to WordPress, Posterous, Typepad, and other similar CMS powered sites.
However, full use of Typekit doesn't come without a cost. If you need to use it on more than 2 sites or on a site that gets a high amount of pageviews you will need to pay an annual cost of $49.99, and for sites with a million+ pageviews it costs twice as much. Though, you probably have the money to cover the cost if you're getting over a million pageviews. If not then you may want to rethink your business model.
Pros
Large font library, including Adobe fonts
Easy implementation
Google Webfont API and blogging platform integration
Free plan has limits but doesn't expire
Cons
Requires JavaScript to use
Limited font library access without paying
Free and cheapest plans only allow use on 1-2 web sites and 2-5 fonts per site
You have to pay to use it on more than 1 site
Scalable Inman Flash Replacement (sIFR)◊
We do not recommend that you use this method but because of how widely used it is we felt it was necessary to include so you could make a properly informed decision when choosing which method to go with for customized webfonts.
Despite its wide popularity among web designers, and its decent support in most browsers, the drawbacks to its use outweigh its convenience. The biggest and most obvious reason to not use sIFR is the fact that it uses Flash. Plus, in order for the Flash to even work, it requires JavaScript and the scripts must be loaded before the text you use it on is visible on the page. Not to mention that it increases page load time, and can cause a slow site to be even slower.
We'll let you do the math here.
Pros
Text can be selected
Support on most browsers
Renders okay on supported browsers
Cons
It uses Flash
Requires JavaScript for the Flash to work
It's Flash!
Text doesn't appear until the scripts load
...and it's Flash...
Font Licensing◊
Even though you can transform just about any font into a web font file, you should still make sure it is legally okay for you to do so. Many foundries have updated their conditions to specify how their fonts can be used on the web. View Font Licensing and Protection Details for more information.
Specifications & Font File Formats◊
CSS 2 Fonts – May 1998 (Obsolete)
CSS 3 Fonts – Working Draft 2009
CSS Fonts Module – W3C Working Draft March 2011
WOFF Font Format – Working Draft 2010
SVG Font Format
Embedded Open Type (EOT) File Format
Microsoft Open Type Specification
OpenType Feature File Specification
Apple True Type Reference
JavaScript◊Back to Top
JavaScript is the third major component of a web page. JavaScript code, when properly applied to a web page, enhances the overall user and browser-based experience through attaching to events and controlling the overall behavior layer.
JavaScript has seen an explosion in popularity in recent years as powerful new browser implementations have finally empowered the creation of full on browser-based web applications. Additionally, careful use of JavaScript allows for full manipulation and control over the other two components of web page authoring, HTML Markup and CSS. Today the structure of pages and the visual styles of pages can be manipulated real time without full web page refreshes.
JavaScript Libraries◊
We primarily develop new applications in jQuery, though we have expertise in plain JavaScript as well as all major modern javascript libraries.
General Coding Principles◊
99% of code should be housed in external javascript files. They should be included at the END of the BODY tag for maximum page performance.
Don't rely on the user-agent string. Do proper feature detection. (More at Dive Into HTML5: Detection & jQuery.support docs)
Don't use document.write().
All Boolean variables should start with "is".
Test for positive conditions
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isValid = (test.value >= 4 && test.success);
Name variables and functions logically: For example: popUpWindowForAd rather than myWindow.
Don't manually minify. With the exception of the traditional i, etc. for for loops, variables should be long enough to be meaningful.
Documentation should follow NaturalDocs structure.
Constants or configuration variables (like animation durations, etc.) should be at the top of the file.
Strive to create functions which can be generalized, take parameters, and return values. This allows for substantial code reuse and, when combined with includes or external scripts, can reduce the overhead when scripts need to change. For example, instead of hard coding a pop-window with window size, options, and url, consider creating a function which takes size, url, and options as variables.
Comment your code! It helps reduce time spent troubleshooting JavaScript functions.
Don't waste your time with comments surrounding your inline javascript, unless you care about Netscape 4. :)
Organize your code as an Object Literal/Singleton, in the Module Pattern, or as an Object with constructors.
Minimize global variables - the less globals you create, the better. Generally one, for your application namespace, is a good number.
When specifying any global variable, clearly identify it
1.
window.globalVar = { ... }
White-space◊
In general, the use of whitespace should follow longstanding English reading conventions. Such that, there will be one space after each comma and colon (and semi-colon where applicable), but no spaces immediately inside the right and left sides of parenthesis. In short, we advocate readability within reason. Additionally, braces should always appear on the same line as their preceding argument.
Consider the following examples of a JavaScript for-loop...
Correct
1.
for (var i = 0, j = arr.length; i < j; i++) {
2.
// Do something.
3.
}
Incorrect
1.
for ( var i = 0, j = arr.length; i < j; i++ )
2.
{
3.
// Do something.
4.
}
Also incorrect
1.
for(var i=0,j=arr.length;i2.
// Do something.
3.
}
plugins.js and script.js◊
Starting with H5BP we're presented with two files, plugins.js and script.js. This section outlines basic usage of these two files.
plugins.js◊
Plugins.js is meant to hold all of a sites plugin code. Instead of linking to many different files, we can improve performance by including plugin code directly in this one file. There can and should be exceptions to this usage. An extremely large plugin only used on one rarely visited page, for example, might be better off in a separate download, only accessed on the target page. Most of the time, however, it's safe to just paste in minified versions of all your plugins here for easy access.
Here's what an example file might looks like, including a small table of contents. This can serve as a handy guide for what plugins are in use, including URLs for documentation, rationale for use and the like.
01.
/* PLUGIN DIRECTORY
02.
What you can find in this file [listed in order they appear]
03.
42.
/*
43.
* jQuery Styled Select Boxes
44.
* version: 1.1 (2009/03/24)
45.
* @requires jQuery v1.2.6 or later
46.
*
47.
* Examples and documentation at: http://code.google.com/p/lnet/wiki/jQueryStyledSelectOverview
48.
*
49.
* Copyright (c) 2008 Lasar Liepins, liepins.org, liepins@gmail.com
50.
*
51.
* Permission is hereby granted, free of charge, to any person obtaining a copy
52.
* of this software and associated documentation files (the "Software"), to deal
53.
* in the Software without restriction, including without limitation the rights
54.
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
55.
* copies of the Software, and to permit persons to whom the Software is
56.
* furnished to do so, subject to the following conditions:
57.
*
58.
* The above copyright notice and this permission notice shall be included in
59.
* all copies or substantial portions of the Software.
60.
*
61.
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
62.
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
63.
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
64.
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
65.
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
66.
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
67.
* THE SOFTWARE.
68.
*
69.
*/
70.
71.
jQuery.fn.styledSelect = function(settings) {
72.
//SNIPPED
73.
return this;
74.
};
Script.js◊
Script.js is meant to hold your site or application code. Again, this isn't always the best solution as larger teams and or larger, more feature rich projects can really benefit from breaking out application code into module or feature specific files. For smaller sites, simpler applications, and initial prototyping, however, dropping your work into scripts.js makes sense.
A simplified example, using the Markup-based unobtrusive comprehensive DOM-ready execution pattern, might look something like the following:
01.
/* Name: Demo
02.
Author: Demo King */
03.
/*demo namespace*/
04.
demo = {
05.
common : {
06.
init : function(){
07.
//initialize
08.
},
09.
finalize : function(){
10.
//finalize
11.
},
12.
config : {
13.
prop : "my value",
14.
constant : "42"
15.
}
16.
},
17.
mapping : {
18.
init : function(){
19.
//create a map
20.
},
21.
geolocate : function(){
22.
//geolocation is cool
23.
},
24.
geocode : function(){
25.
//look up an address or landmark
26.
},
27.
drawPolylines : function(){
28.
//draw some lines on a map
29.
},
30.
placeMarker : function(){
31.
//place markers on the map
32.
}
33.
}
34.
}
Variables, ID & Class◊
All JavaScript variables shall be written in either completely lowercase letter or camelCase. The one exception to this are Constructor functions, which are capitalized by tradition. All id and class declarations in CSS shall be written in only lowercase. Neither dashes nor underscores shall be used.
Event Delegation◊
When assigning unobtrusive event listeners, it is typically acceptable to assign the event listener directly to the element(s) which will trigger some resulting action. However, occasionally there may be multiple elements which match the criteria for which you are checking, and attaching event listeners to each one might negatively impact performance. In such cases you should use event delegation instead.
jQuery's delegate() is preferred over live() for performance reasons.
Debugging◊
Even with the best of validators, inevitably browser quirks will cause issues. There are several invaluable tools which will help to refine code integrity and loading speed. It is important that you have all of these tools available to you, despite the browser you primarily use for development. We recommend developing for Firefox and Safari first, then Google Chrome and Opera, with additional tweaks via conditional comments just for Internet Explorer. The following is a list of helpful debuggers and speed analyzers...
Firefox: Firebug, Page Speed, YSlow
Safari: Web Inspector
Google Chrome: Developer Tools
Opera: Dragonfly
Internet Explorer 6-7: Developer Toolbar
Internet Explorer 8-10: Developer Tools
Patterns for better JavaScript◊
Writing Maintainable Code
Single var Pattern
Hoisting: A Problem with Scattered vars
(Not) Augmenting Built-in Prototypes
Avoiding Implied Typecasting
Avoiding eval()
Number Conversions with parseInt()
Opening Brace Location
Capitalizing Constructors
Writing Comments
Avoid void
Avoid with Statement
Avoid continue Statement
Avoid Bitwise Operators if possible
Stoyan Stefanov covers these and more in detail here.
Accessibility◊Back to Top
Section 508 Standards for intranet and internet information and applications.
— Interfaces developed by Isobar should meet Section 508 standards.
W3C checklist of checkpoints for accessibility.
— Interfaces developed by Isobar should meet Priority 1 guidelines.
— The WCAG 1.0 Guidelines.
Performance◊Back to Top
As we continue to push the limits of what the web can do, it remains just as important a web page can be used with minimal effort or wait time. The following section explains how web pages can be optimized to keep all audiences happy.
Optimize Delivery of CSS and JavaScript◊
There are many optimizations that should be done for serving CSS and javascript in Production:
Follow the Yahoo Performance Guidelines
Smush images using smush.it. Also using YSlow can autosmush all your images for you.
Set caching headers appropriately.
Consider a cookie-less subdomain for static assets
Avoid inline
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