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AJAX Browser Support

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:

<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.

Note: The code above can be used every time you need to create an XMLHttpRequest object, so just copy and paste it whenever you need it.

The next chapter shows how to use the XMLHttpRequest object to communicate with a server.

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