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The XMLHttpRequest
(XHR) objects is a core of Ajax used to interact with servers. This helps you to retrieve data from a URL without having to do a full page refresh. This enables a Web page to update just part of a page without reloading the whole page.
Note: Despite its name, XMLHttpRequest
can be used to retrieve any type of data, not just XML.
In the following example, we request a URL and receive a response.
Value | Explanation |
---|---|
abort() | Terminate the current request. |
getAllResponseHeaders() | Returns all the response headers |
getResponseHeader() | Returns the string containing the text of a particular header's value. |
new XMLHttpRequest() | Creates a new XMLHttpRequest. |
open(method,url,async,user,pass) | Initializes a newly-created request, or re-initializes an existing one.
Parameters Explanation
|
send(data) | sends the request to the server. |
setRequestHeader() | Sets the value of an HTTP request header. |
Value | Explanation |
---|---|
onreadystatechange | Specifies a function which is called from the user interface thread. |
readyState | Returns the state an XMLHttpRequest client is in.
Possible values are
|
responseText | Returns the text received from a server following a request being sent. |
responseXML | Returns a Document containing the HTML or XML retrieved by the request. |
status | Returns the numerical HTTP status code of the XMLHttpRequest's response. |
statusText | Returns a DOMString containing the response's status message as returned by the HTTP server. |
Device | ![]() | ![]() | |||||||||||
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Browser | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() |
XMLHttpRequest() | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
For security reasons, browsers do not allow access across domains.
For example: From www.abc.com you can't send XMLHttpRequest to www.xyz.com.
All resources of www.abc.com can only be accessed by itself.