Web New Media notes and ramblings

JQuery is a great tool for web development. It’s a Javascript framework that makes working with Javascript much easier. JQuery makes it easier to write code that works across platforms. JQuery simplifies all of the common Javascripts that may need to perform.

Download the JQuery library from Jquery.com. They archive different versions and provide a compressed (or minified) version and an un-compressed version. You can download the latest compressed version from the JQuery home page and it will work with all of the examples. Move this file into the directory where you will be working.

You can obviously place the jquery js file anywhere, as long as you provide the correct path to the file in your HTML document.

JQuery is very easy to use. Follow these steps:

1. Import the JQuery js file with the script tag
2. Set up another script tag for your own javascript.

For example:

<script type="text/javascript" src='jquery-1.4.4.min.js'></script>
<script type="text/javascript">
   // your own JS here
</script>

At this point you can use JQuery in your scripts. Notice, your scripts come second.

Many times you will want to wait for your document to load before applying your own JS. This important, because executing JS before the elements it acts on are loaded will cause your scripts to fail. JQuery provides the ready() event to easily work around this.

To set up the ready event use the following:

<script type="text/javascript" src='jquery-1.4.4.min.js'></script>
<script type="text/javascript">
$(document).ready(function(){
   // Scripts here execute after the page has loaded.
});
</script>

The background-size property determines how a background image fills an area. The size and method used to fill the space has several options. Here’s an example that fills the background with an image, resizing the image to fill the space.

Background-size example

It may take a moment to load the background image. After the background loads resize the browser window. Notice the image always fills the space.

Identifiers are the names that you invent to represent or identify elements in the program. Identifiers can be used to name MovieClip instances, Classes, Variables and Functions.

The program comes with many built elements that already have names. These are things like MovieClip methods like gotoAndStop() etc. You should avoid using these names as names for your own elements.

When creating Identifier names you should follow the following rules.

• Names must begin with a letter (a,b,c etc) the underscore (_) or the dollar sign ($).
• Names can contain any combination of letters, numbers and the underscore and dollar sign.
• Avoid using names have already been used by the program.

Conventions

Identifiers are used fro various purposes. Following conventions while creating identifier names will help you keep them all straight.

In general identifiers should be kept lower case.

Class names: Class names always begin with an upper case letter. All of the built in classes follow this convention. For example MovieClip, Sprite and EventDispatcher all start with an uppercase letter.

Private Properties: A common convention is to start private properties with an underscore. For example: _index, _width, _height etc. The definitions for these might look like:

private var _index:uint;
private var _width:Number;
private var _height:Number;