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You use Javascript to animate your website, but your code lacks of structure. Your JavaScript functions are scattered in <script>
tags placed all around and you would like to clean this up? Then Dojo is
for you.
Installing Dojo
The installation of Dojo is done in three steps: download, inclusion on the site and loading Dojo when the opening the site.
Download Dojo
The best way to get Dojo is to go directly to download the latest stable version from the official website: http://dojotoolkit.org/download/
Installing Dojo
Once downloaded, you will have three folders: "dojo", "dijit" and "dojox" (the latter is in fact an extension of the basic framework).
Copy the three folders to the root of your website (or in a subfolder).
Loading Dojo when the opening the site
Last step, the most important: ask the user's browser to load the
framework when loading the site. For this, simply place the following in
the "head": a tag source in the "head"
<head>
<script src=\"../../dojo/dojo.js\" type=\"text/javascript\"></script>
</head>
Where "dojo.js" is the main page of the Javascript framework. Simply
edit the path to the dojo folder according to your current
installation!
That's it! Dojo is now ready for use on your site!
Using Dojo
How to use the framework?
The addOnLoad method
The dojo.addOnLoad() method: This method is called when the site us loaded. To end the session simply use the dojo.addOnUnload() method, upon closing the website.
Simply place in the home page of your site a JS script calling this method:
<script type="text/javascript">
dojo.addOnLoad(
function() {
// Place the code to be launch when site is loaded here
}
);
</script>
The "Application" class
Here below, you will learn how to create a Javascript class via Dojo, using the "Application" class.
Start by creating a "Application.js" file.
To illustrate its use, let's pretend that this class is at the root
of the site, in the "mysite" folder, and in the "javascript" subfolder: /mysite/javascript/
Ceating a JS class:
dojo.provide('mysite.javascript.Application');
dojo.declare('mysite.javascript.Application', null, {
myFirstArgument: null,
mySecondArgument: null,
constructor: function(param1, param2) {
myFirstArgument = param1;
// Class constructor code.
},
method1: function(param){
},
method2: function(){
}
});
Here we see several things:
- The dojo.provide function is called, as parameter we used the
path to the class file. This allows Dojo "know" that the Application
class exists.
- The dojo.declare function is called, in which the code for the Application class is found. This method takes three parameters:
- the classpath
- a boolean
- the content of the class, namely:
- the attributes of classes, initialized to "null" and followed by a comma.
- the first method: the constructor, which may or may not have parameters.
- The other class method (optional).
- Finally braces and closing parentheses of the method stated.
Each attribute and method is followed by a comma to separate it from other, except the last.
Contents of the Application class
As example:
dojo.provide ('monsite.javascript.Application');
dojo.declare ('monsite.javascript.Application', null, {
_user: null,
constructor: function (userParam) {
this._utilisateur = userParam;
}
start: function () {
alert (this._utilisateur);
}
});
Specifically, here we will create the Application class with a
string as parameter, pass the parameter attribute, and then call a
method "start ()" which will display this string.
Calling the Class
Back to dojo.addOnLoad. Here we will create an instance of our application class and display a specific string.
The code is as follows:
<script type="text/javascript">
dojo.addOnLoad(
function() {
dojo.require('monsite.javascript.Application');
var appli = new monsite.javascript.Application("Salut CommentCaMarche");
appli.start();
}
);
</script>
The steps are:
- Call the dojo.require() method
- Creating an instance of the Application class using a constructor.
- Call the start() method of the Application class, which therefore responsible for displaying the previous string.
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