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.