AJAX - Browser support

Mon Aug 17, 2009 1:20 pm

AJAX - Browser support
The keystone of AJAX is the XMLHttpRequest object.

All new browsers use the built-in JavaScript XMLHttpRequest object to create an XMLHttpRequest object (IE5 and IE6 uses an ActiveXObject).

Let's update our "testAjax.htm" file with a JavaScript that creates an XMLHttpRequest object:

Code:: <html> <body> <script type="text/javascript"> function ajaxFunction() { var xmlhttp; if (window.XMLHttpRequest) { // code for IE7+, Firefox, Chrome, Opera, Safari xmlhttp=new XMLHttpRequest(); } else if (window.ActiveXObject) { // code for IE6, IE5 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } else { alert("Your browser does not support XMLHTTP!"); } } </script> <form name="myForm"> Name: <input type="text" name="username" /> Time: <input type="text" name="time" /> </form> </body> </html>

Example explained

1. Create a variable named xmlhttp to hold the XMLHttpRequest object.

2. Try to create the XMLHttpRequest object with xmlhttp=new XMLHttpRequest().

3. If that fails, try xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"). This is for IE6 and IE5.

4. If that fails too, the user has a very outdated browser, and will get an alert stating that the browser doesn't support XMLHTTP.

AJAX - Browser support

AJAX - Browser support

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