Basic PHP development tutorial: Creating XMLHttpRequest

1. Create an XMLHttpRequest object

1. XMLHttpRequest is the basis of AJAX

2. XMLHttpRequest Object

• The XMLHttpRequest object is supported by all modern browsers (IE5 and IE6 use ActiveXObject).

• XMLHttpRequest is used to exchange data with the server in the background. This means that parts of a web page can be updated without reloading the entire page.

3. Syntax for creating XMLHttpRequest object:

All modern browsers (IE7+, Firefox, Chrome, Safari and Opera) have built-in XMLHttpRequest object.

• Syntax for creating an XMLHttpRequest object:

variable=new XMLHttpRequest();

• Old Versions of Internet Explorer (IE5 and IE6) use ActiveX objects:

variable=new ActiveXObject("Microsoft.XMLHTTP");

• For For all modern browsers, including IE5 and IE6, please check whether the browser supports the XMLHttpRequest object. If supported, creates an XMLHttpRequest object. If not supported, create an ActiveXObject:

var xmlhttp;
if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
  }
else
  {// code for IE6, IE5
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }