XMLHttpRequest (XHR) objects are used to interact with servers. You can 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 disrupting what the user is doing.
XMLHttpRequest is used heavily in AJAX programming.
Despite its name, XMLHttpRequest can be used to retrieve any type of data, not just XML.
If your communication needs to involve receiving event data or message data from a server, consider using server-sent events through the EventSource interface. For full-duplex communication, WebSockets may be a better choice.
Returns a Document containing the response to the request, or null if the request was unsuccessful, has not yet been sent, or cannot be parsed as XML or HTML. Not available in Web Workers.
Returns a string containing the response string returned by the HTTP server. Unlike XMLHttpRequest.status, this includes the entire text of the response message ("OK", for example).
Returns the string containing the text of the specified header, or null if either the response has not yet been received or the header doesn't exist in the response.
Fired when a request has been aborted, for example because the program called XMLHttpRequest.abort(). Also available via the onabort event handler property.
Fired when a request has completed, whether successfully (after load) or unsuccessfully (after abort or error). Also available via the onloadend event handler property.
75Implemented via ActiveXObject('Microsoft.XMLHTTP')
8
1.2
≤37
18
4
10.1
1
1.0
abort
1
12
1
5
≤12.1
1.2
4.4
18
4
≤12.1
1
1.0
abort_event
1
12
3.5
10
≤12.1
1.3
≤37
18
4
≤12.1
1
1.0
authorization_removed_cross_origin
No
No
111
No
No
16.1
No
No
111
No
16.1
No
error_event
1
12
1
10
≤12.1
1.3
≤37
18
4
≤12.1
1
1.0
getAllResponseHeaders
1
12
1Starting from Firefox 49, empty headers are returned as empty strings in case the preference network.http.keep_empty_response_headers_as_empty_string is set to true, defaulting to false. Before Firefox 49 empty headers had been ignored. Since Firefox 50 the preference defaults to true.
5
≤12.1
1.2
4.4
18
4Starting from Firefox 49, empty headers are returned as empty strings in case the preference network.http.keep_empty_response_headers_as_empty_string is set to true, defaulting to false. Before Firefox 49 empty headers had been ignored. Since Firefox 50 the preference defaults to true.
≤12.1
1
1.0
getResponseHeader
1
12
1Starting from Firefox 49, empty headers are returned as empty strings in case the preference network.http.keep_empty_response_headers_as_empty_string is set to true, defaulting to false. Before Firefox 49 empty headers had been ignored. Since Firefox 50 the preference defaults to true.
5
8
1.2
4.4
18
4Starting from Firefox 49, empty headers are returned as empty strings in case the preference network.http.keep_empty_response_headers_as_empty_string is set to true, defaulting to false. Before Firefox 49 empty headers had been ignored. Since Firefox 50 the preference defaults to true.
10.1
1
1.0
load_event
1
12
1
9
≤12.1
1.3
≤37
18
4
≤12.1
1
1.0
loadend_event
18
12
5
10
≤12.1
4
4.4
18
5
≤12.1
3
1.0
loadstart_event
1
12
3.5
10
≤12.1
1.3
4.4
18
4
≤12.1
1
1.0
open
1
12
1Starting in Firefox 30, synchronous requests on the main thread have been deprecated due to their negative impact on performance and the user experience. Therefore, the async parameter may not be false except in a Worker.
5
8
1.2
4.4
18
4Starting in Firefox 30, synchronous requests on the main thread have been deprecated due to their negative impact on performance and the user experience. Therefore, the async parameter may not be false except in a Worker.
10.1
1
1.0
overrideMimeType
1
12
1
115Implemented via ActiveXObject
≤12.1
1.2
4.4
18
4
≤12.1
1
1.0
progress_event
1
12
1
10
≤12.1
3
≤37
18
4
≤12.1
1
1.0
readyState
1
12
1
7
8
1.2
4.4
18
4
10.1
1
1.0
readystatechange_event
1
12
1
5
9
1.2
4.4
18
4
10.1
1
1.0
response
9
12
6
10
11.6
5.1
3
18
6
12
5
1.0
responseText
1
12
1
5Before Internet Explorer 10, the value of XMLHttpRequest.responseText could be read only once the request was complete.
8
1.2
4.4
18
4
10.1
1
1.0
responseType
31
12
6
10
1812–15
5.1
4.4.3
31
50
1812–14
5
2.0
responseURL
37
14
32
No
24
8
37
37
32
24
8
3.0
responseXML
1
12
1Before Firefox 51, an error parsing the received data added a <parsererror> node to the top of the Document and then returned the Document in whatever state it happens to be in. This was inconsistent with the specification. Starting with Firefox 51, this scenario now correctly returns null as per the spec.
7
≤12.1
3
≤37
18
4Before Firefox 51, an error parsing the received data added a <parsererror> node to the top of the Document and then returned the Document in whatever state it happens to be in. This was inconsistent with the specification. Starting with Firefox 51, this scenario now correctly returns null as per the spec.
≤12.1
1
1.0
send
1
12
1
5
8
1.2
4.4
18
4
10.1
1
1.0
setAttributionReporting
117
117
No
No
103
No
117
117
No
No
No
No
setPrivateToken
117
117
No
No
103
No
117
117
No
No
No
No
setRequestHeader
1
12
1
5
8
1.2
4.4
18
4
10.1
1
1.0
status
1
12
1
7Internet Explorer version 5 and 6 supported ajax calls using ActiveXObject()
8
1.2
4.4
18
4
10.1
1
1.0
statusText
1
12
1
7Internet Explorer version 5 and 6 supported ajax calls using ActiveXObject()
≤12.1
1.2
4.4
18
4
≤12.1
1
1.0
timeout
29
12
12
8
1712–16
7
4.4
29
14
1812–16
7
2.0
timeout_event
29
12
12
8
16
7
4.4
29
14
16
7
1.0
upload
2
12
3.5
10
≤12.1
4
4.4
18
4
≤12.1
3
1.0
withCredentials
3
12
3.5Starting with Firefox 11, it's no longer supported to use the withCredentials attribute when performing synchronous requests. Attempting to do so throws an NS_ERROR_DOM_INVALID_ACCESS_ERR exception.
10Internet Explorer versions 8 and 9 supported cross-domain requests (CORS) using XDomainRequest.
12
4
≤37
18
4Starting with Firefox 11, it's no longer supported to use the withCredentials attribute when performing synchronous requests. Attempting to do so throws an NS_ERROR_DOM_INVALID_ACCESS_ERR exception.