AJAX - Create an XMLHttpRequest Object
The keystone of AJAX is the XMLHttpRequest object.
The XMLHttpRequest Object
All modern browsers support the XMLHttpRequest object (IE5 and IE6 uses an ActiveXObject).
The XMLHttpRequest object is used to exchange data with a server behind the
scenes. This means that it is possible to update parts of a web page, without
reloading the whole page.
Create an XMLHttpRequest Object
All modern browsers (IE7+, Firefox, Chrome, Safari, and Opera) has a built-in XMLHttpRequest object.
Syntax for creating an XMLHttpRequest object:
| xmlhttp=new XMLHttpRequest(); |
Old versions of Internet Explorer (IE5 and IE6) uses an ActiveX Object:
| xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); |
To handle all modern browsers, including IE5 and IE6,
check if the browser supports the XMLHttpRequest object. If it does, create an
XMLHttpRequest object, if not, create an ActiveXObject:
Example
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
} |
View it » |
In the next chapter you will learn about sending server requests.
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