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Where Ajax comes from

Ajax means Asynchronous Javascript And XML. Ajax is based on Javascript and it was made very popular because Google use it widely in their applications.

How Ajax will help you

Each time you need to bring pieces of information into your webpage, you should think of Ajax. Ajax helps a webpage to look more to a desktop application avoiding the page to completly reload each time something changes. With Ajax you refresh only a small part of the page (generally a DIV) by calling a server request using the XMLHttpRequest object.

The following example will set a simple form with a textbox with a clear password and a button. Each time, you provide a password and press the button, Ajax will trigger a call to a server script that will execute a simple algorithm to calculate the password strength.

Demo

Making a simple request

First lets create a very simple HTML form. The HTML file will be called ajaxtest.html and will be as follow:

Then add the Javascript function goAjax into the header of you HTML file. It will look like this:

After your HTML file is complete, we need to write the server script that will give you the result. In this case, we will make a simple routine for password strength calculation, based on weight attribution providing it contains a mix of lower case, upper case, special characters and numbers:

History

2008-07-16: First version