Bo Allen's Web Coding Standards

This is a very basic set of web coding standards aimed to maintain code consistency.

General Practices

Indentation and Line Breaks

All indentation is done with 4 spaces, not tabs.
Why spaces?

Line breaks must be in UNIX format (LF: Line Feed, U+000A, chr(10), \n).

Maximum Line Length

Lines of code should not exceed 120 characters.

Naming Conventions

Everything falls into one of five of the following naming conventions:

An underscore (not a dash) replaces a space.

Private and protected variables begin with an underscore.

Indent Style

K & R Style: Variant 1TBS
http://en.wikipedia.org/wiki/Indent_style#Variant:_1TBS

Correct
function favorite_indent_style($style) {
    if ($style != '1TBS') {
        return false;
    } else {
        return true;
    }
}

Cross Browser Testing

The latest versions of the following browsers should be tested for compatibility.

Be aware that as of April 2009, statistics show that as much as 10% of all browser traffic is still IE6. Testing is at your discretion.

Third-Party Development

When using a third-party framework or library, the coding standards of that framework or library should be used.

HTML

Doctype

XHTML 1.0 Transitional will be used (until HTML5 is solidly supported (2012? 2022?)).

Valid XHTML 1.0 Transitional Template 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml"> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 
<title>Valid XHTML 1.0 Transitional Template</title>
</head>
<body>
</body> 
</html>

Layout

The div element is to be used for layout elements. HTML tables are intended for tabular data only.

All div elements with an id attribute must be marked at the closing div. See the example below.

Correct
<div id="header">
    <h1>Title</h1>
</div> <!-- /#header -->

Self-closing Elements

A space is required before the forward slash of a self-closing element.

Correct
<br />
Incorrect
<br/>

Tags and Attributes

All tags and attributes must be written in lowercase. Additionally, it is preferred that any attribute values also be lowercase, when the purpose of the text therein is only to be interpreted by machines. For instances in which the data needs to be human readable, proper title capitalization should be followed, such as:

For machines
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
For humans
<a href="http://example.com/" title="Description Goes Here">Example.com</a>

Quotes

In keeping with the strictness of XHTML code conventions, according to the W3C, all attributes must have a value, and must use double-quotes. The following are examples of proper and improper usage of quotes and attribute/value pairs.

Correct
<input type="text" name="email" disabled="disabled" />
Incorrect
<input type=text name=email disabled>

CSS

Inline Styles

Inline style attributes are not allowed (style="..."). Internal style declarations are allowed when they make sense. Please use external stylesheets.

An exception to this rule is style="display: none;" for revealing hidden elements via JavaScript.

CSS Validation

All cascading stylesheets should be verified against the W3C validator, to ensure correct syntax and to check for possible accessibility issues with text and background colors. This in and of itself is not directly indicative of good code, but it helps to weed out problems that are able to be tested via automation. It is no substitute for manual code review.

Validation errors related to -moz*, -khtml*, -webkit*, and opacity should be considered "warnings" rather than errors. Just be sure to cross-browser test your styles.

CSS Formatting

To ease potential headaches for maintenance, all CSS must be written in a consistent manner. For one, all CSS selectors must be listed on their own line. As a general rule of thumb, if there is a comma in CSS, it should immediately be followed by a line break. This way, we know that all text on a single line is part of the same selector. Likewise, all property/value pairs must be on their own line with standard indentation (4 spaces), and end with a semicolon. All property values must begin with a space (after the colon). The closing brace must be on the same level of indentation as the selector that began it - flush left.

Correct
#selector-1 span,
#selector-2 span,
#selector-3 span {
    background: #fff;
    color: #000;
}
Incorrect
#selector_1 span, #selector_2 span, #selector_3 span {
    background:#fff; color: #000
}
Also incorrect
#selector { background: #fff; color: #000; }

Pixels vs. Ems

Use the px unit of measurement to define font size, because it offers absolute control over text.

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.

Do not use the pt unit for screen media (i.e., print only).

Correct
.selector {
    font-size: 13px;
    line-height: 1.5;
}
Incorrect
.selector {
    font-size: 0.813em;
    line-height: 1.25em;
}

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 it is we encouraged to troubleshoot and build code that will work in all browsers without special modifications, sometimes it is necessary to use conditional if IE comments to serve up specific fixes, which are ignored by other browsers.

Fixing IE
<!--[if IE 7]>
<link type="text/css" rel="stylesheet" href="/assets/styleshseets/ie7.css" />
<![endif]-->

<!--[if IE 8]>
<link type="text/css" rel="stylesheet" href="/assets/styleshseets/ie8.css" />
<![endif]-->

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:

Margin & Padding

Correct

#selector {
    margin: 0 0 10px;
    padding: 0 0 10px;
}
Incorrect - left attribute unnecessary 
#selector {
    margin: 0 0 10px 0;
    padding: 0 0 10px 0;
}

Hex Colors

We prefer hex values for all colors, written in lower-case. No upper-case or RGB, please! Additionally, all colors should be written as tersely as possible. This means that colors such as full blue, which can be written lengthily as #0000FF, should be simply written as #00f. Obviously, for colors that require more precision, all six characters should be used. For example, a light shade of grayish beige: #f9f9f0.

Background

Correct - shorthand
#selector {
    background: #fff url(../images/file.png) repeat-x fixed left bottom;
}
Incorrect - longhand unnecessary
#selector {
    background-color: #fff;
    background-image: url(../images/file.png);
    background-repeat: repeat-x;
    background-attachment: fixed;
    background-position: left bottom;
}

Border

In general, border should be a single line declaration, assuming that the values of the border are the same on all sides of the element. The order in which values are declared are: width, style, and color.

Shorthand - method 1
#selector {
    border: 1px solid #000;
}

If the values of each side differ, then there are two possible ways of using shorthand, and it is up to the discretion of the developer to decide which to use. Note that method 2 follows the TRBL pattern.

Shorthand - method 2
#selector {
    border-color: #fff #999 #666 #ccc;
    border-style: solid dashed dotted double;
    border-width: 1px 2px 3px 4px;
}
Shorthand - method 3
#selector {
    border-top: 1px solid #fff;
    border-right: 2px dashed #999;
    border-bottom: 3px dotted #666;
    border-left: 4px double #ccc;
}

Font

Not to be confused with the inadvisable <font> tag, the CSS font property can be written in a few different ways. The shorthand property puts all the aspects of the font into a single declaration, whereas the longhand splits it out over several lines. While the contrast between methods is not as stark as with that of the border property, there is still space to be saved by using shorthand. While line-height can be defined within the scope of the font declaration, but when written in longhand it has its own unique property.

Times New Roman is encapsulated in quotes, because the font name itself contains spaces.

Shorthand
#selector {
    font: italic small-caps bold 15px/1.5 Cambria, 'Times New Roman', sans-serif;
}
Longhand
#selector {
    font-style: italic;
    font-variant: small-caps;
    font-weight: bold;
    font-size: 15px;
    line-height: 1.5;
    font-family: Cambria, 'Times New Roman', sans-serif;
}

Longhand

When overriding only parts of a style, longhand declaration is preferred. This way, by sticking to shorthand for initial style declarations, anytime a longhand declaration used, it could be deduced that it is overriding only a very precise part of an overall style, thereby leaving other aspects unaffected.

Longhand override
#selector {
    border: 1px solid #ccc;
    font: 11px Verdana, sans-serif;
}
#selector.modifier {
    border-bottom-color: #333;
    border-bottom-width: 2px;
    font-family: Georgia, serif;
}

Javascript

Type Coercion

Unlike strongly typed languages such as Java or C#, JavaScript will perform type coercion when evaluating conditional statements. This sometimes creates awkward scenarios in which numerical values are seen as false or the existence of a string is mistaken for true. This is typically disadvantageous.

To ensure a strict level of comparison, as might be seen in a strongly typed or compiled language, JavaScript (like PHP) has a triple-equals operator ===. In similar fashion, it also has a strict negation operator !==. Consider the following examples of potential pitfalls when it comes to evaluating comparisons.

var test_1 = 'true';
var test_2 = 0;

if (test_1 == true) {
    // Code here will run. But it shouldn't.
}

if (test_1 === true) {
    // Code here won't run. Correct behavior.
}

if (test_2 != false) {
    // Code here won't run. But it should.
}

if (test_2 !== false) {
    // Code here will run. Correct behavior.
}

As you can see in the example above, simply using == and != is insufficient because it makes for potentially unpredictable results. Therefore, the stricter comparison operators should always be used. There is never a good reason to use the lesser form of comparison operators. To simply for the existence of elements in the DOM, there is an even more abbreviated way, that leaves no room for ambiguity. If you are unsure if certain elements will be present in an HTML page, use one of the following techniques.

function first_func() {
    if (!document.getElementById('id_name')) {
    return;
}
// If code gets here, element exists.

}
function second_func() {
    if (!document.getElementsByTagName('div').length) {
    return;
}
// If code gets here, one or more exist.
}

Whitespace

In general, the use of whitespace should follow longstanding English reading conventions. I.e., 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
for (var i=0, j=arr.length; i<j; i++) {
    // Do something.
}
Incorrect
for ( var i = 0, j = arr.length; i < j; i++ )
{
    // Do something.
}

Variables

All JavaScript variables shall be written in lowerCamelCase, because every variable in Javascript is a property of an object.

Quotes

The preferred method of delineating strings is to use single quotes for everything. Since JavaScript exists to manipulate markup, and because HTML is generally written with double quotes in W3C specifications, using single quoted strings will better facilitate handling HTML fragments, and keep code more readable.

Correct
var my_html = '<img class="photo" src="/path/file.jpg" alt="Text" />';
Incorrect
var my_html = "<img class=\"photo\" src=\"/path/file.jpg\" alt=\"Text\" />";

Event Listeners

Rather than using attributes such as onload, onfocus, onsubmit, or onclick directly in markup, we will instead attach event listeners to these elements via unobtrusive techniques. The reasoning for this is the same philosophy that is behind not using inline declarations. So doing inextricably ties the behavior of a web page to its data, and makes maintenance more difficult.

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.

Closures & Scope

To maintain proper scope for variables, it is highly recommended that self-executing anonymous function be used as a closure. For the most part, variables defined correctly using the var syntax, within the scope of a function will not add to global scope pollution. However, from time to time, you may need to access variables via two or more functions. In such cases, multiple functions can be grouped together inside a closure.

Closure
(function() {
    var first_variable = 'value 1';
    var second_variable = 'value 2';

    function first_func() {
        // Do something.
    }

    function second_func() {
        // Do something.

    }
})();

Objects & Arrays

Objects can be thought of as tiered variables that contain multiple attributes. Similarly, an array could be described as a list of data that all share common characteristics. The following code snippets show examples of objects and arrays, and the different ways in which they can be defined. Note that values such as John Doe's age and marital status do not have quotation marks around them. This is because age is truly numerical, and true is a Boolean value.

Note also that the commas are before the variable or method declaration. This prevents errors with trailing commas in IE and other browsers.

Objects (and arrays) are an important part of JSON - JavaScript Object Notation, which is a platform and language independent way of transmitting data, used as an alternative to XML.

Object literal - preferred
var john_doe = {
    first_name: 'John'
    ,last_name: 'Doe'
    ,job: 'Everyman Respresentative'
    ,email: 'john.doe@example.com'
    ,married: true
    ,age: 30
};
Object dot notation

/*
Could also be written:
var john_doe = new Object();
*/
var john_doe = {};
john_doe.first_name = 'John';
john_doe.last_name = 'Doe';
john_doe.job = 'Everyman Representative';
john_doe.email = 'john.doe@example.com';
john_doe.married = true;
john_doe.age = 30;
Array literal - preferred
var doe_family = [
    'John'
    ,'James'
    ,'Jane'
    ,'Jenny'
    ,'Jared'
    ,'Jerome'
];
Array bracket notation
/*
Could also be written:
var doe_family = new Array();
*/
var doe_family = [];
doe_family[0] = 'John';
doe_family[1] = 'James';
doe_family[2] = 'Jane';
doe_family[3] = 'Jenny';
doe_family[4] = 'Jared';
doe_family[5] = 'Jerome';

PHP

General

Parenthesis

require_once './config.php';

if ($test) {
    // ...
}

if (!$test) {
    // ...
}

while ($test == $other) {
    // ...
}

array_push($one, $two);

return $test;

Classes, Methods, and Properties

class Car {
    
    public $make;
    public $model;
    private $_vin;
    protected $_options;
    
    public function __construct($make, $model, $_vin, $_options) {
        $this->make = $make;
        $this->model = $model;
        $this->_vin = $_vin;
        $this->_options = $_options;
    }
    
    public function getMake() {
        return $this->make;
    }
    
    public function getModel() {
        return $this->model;
    }
    
    private function _getVin() {
        return $this->_vin;
    }
    
    protected function _getOptions() {
        return $this->_options;
    }
}

Functions and Variables

All functions and variables (non-object) will be lower_case.

$user_bio = "I am a ninja, not a pirate.";

function filter_user_bio($bio) {
    str_replace('pirate', '******');
}

Arrays

Constants

File Structure

This page was heavily borrowed from the MODx Revolution Code Standards page. Thanks!