AJAX XMLHttpRequest

Getting to know XMLHttpRequest

Properties of XMLHttpRequest XMLHttpRequest Methods of XMLHttpRequest

An object of XMLHttpRequest is used for communication between the client and the server that happens at different times.

The following things are done with it:

Sends information from the client behind the scenes

takes the information from the server

The page is updated without having to be reloaded.

XMLHttpRequest object\’s properties

The following are the common properties of the XMLHttpRequest object:

The property and what it is

onReadyStateChange

When the readystate attribute changes, it\’s called. It cannot be used with requests that happen at the same time.

readyState

shows where the request is in its process. From 0 to 4, it goes.

0 UNOPENED open() is not run.

1 OPENED: open is called, but not send().

2: send() is called, and HEADERS RECEIVED is returned. Headers and status are now available.

3 LOADING Downloading data; the data are in responseText.

4 DONE The job is done completely.

reponseText

returns response as text.

responseXML

returns response as XML

XMLHttpRequest object methods

These are the most important methods of the XMLHttpRequest object:

Method and Explanation

void open (method, URL)

opens the request by giving the URL and either the get or post method.

void open (method, URL, async)

same as above, but specifies whether or not it is asynchronous.

void open (method, URL, async, username, password)

same as above, but the username and password are given.

void send ()

sends get request.

void send (string)

send post request.

setRequestHeader(header,value)

it adds headers to a request.