AJAX reference

The term AJAX stands for Asynchronous JavaScript and XML and was coined in 2005 by Jesse James Garrett. AJAX is a technique for using the browser's

XMLHttpRequest object to transfer data between the client and the server without causing the page to refresh.

The original XMLHttpRequest object was added as an ActiveX object into Microsoft's Internet Explorer 5 browser in 1999. Afterward, other browsers followed Microsoft's lead with their own implementations of XMLHttpRequest that did not require ActiveX.

XMLHttpRequest

Properties	Description
onreadystatechange	This is set to an event handler function that is called whenever the readyState property changes.
readyState	This an integer value that indicates the status of the request: 0 = Uninitialized 1 = Loading 2 = Loaded 3 = Interactive 4 = Complete
responseText	Text data that is returned from the server.
responseXML	XML data that is returned from the server.
status	This is the HTTP status code returned by the server.
statusText	This is the HTTP text code returned by the server.

Methods	Description
abort()	Call to abort the current request.
getAllResponseHeaders()	Return all of the headers in a string.
getResponseHeader(name)	Return the value of name as a string.
open(type, url, asynch)	Open requests a file download. The type is the type of the request, usually GET or POST, but may be any of the following: GET POST HEAD PUT DELETE OPTIONS The url is the location of the file, with possible parameters tacked on. The parameter asynch is a boolean value that is true if the request is asynchronous.
send(data)	This sends the HTTP request to the server. The data is data that is sent to the server.
setRequestHeader(name, value)	This puts the (name, value) pair in header of the HTTP request.