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---
title: XMLHttpRequest
slug: Web/API/XMLHttpRequest
tags:
- AJAX
- API
- Communication
- HTTP
- Interface
- NeedsTranslation
- Reference
- TopicStub
- Web
- XHR
- XMLHttpRequest
translation_of: Web/API/XMLHttpRequest
---
<div>{{DefaultAPISidebar("XMLHttpRequest")}}</div>
<p><span class="seoSummary">Use <code>XMLHttpRequest</code> (XHR) objects 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.</span> <code>XMLHttpRequest</code> is used heavily in {{Glossary("AJAX")}} programming.</p>
<p>{{InheritanceDiagram(650, 150)}}</p>
<p>Despite its name, <code>XMLHttpRequest</code> can be used to retrieve any type of data, not just XML.</p>
<p>If your communication needs to involve receiving event data or message data from a server, consider using <a href="/en-US/docs/Web/API/Server-sent_events">server-sent events</a> through the {{domxref("EventSource")}} interface. For full-duplex communication, <a href="/en-US/docs/Web/API/WebSockets_API">WebSockets</a> may be a better choice.</p>
<h2 id="Constructor">Constructor</h2>
<dl>
<dt>{{domxref("XMLHttpRequest.XMLHttpRequest", "XMLHttpRequest()")}}</dt>
<dd>The constructor initializes an XMLHttpRequest. It must be called before any other method calls.</dd>
</dl>
<h2 id="Properties">Properties</h2>
<p><em>This interface also inherits properties of {{domxref("XMLHttpRequestEventTarget")}} and of {{domxref("EventTarget")}}.</em></p>
<dl>
<dt id="xmlhttprequest-onreadystatechange">{{domxref("XMLHttpRequest.onreadystatechange")}}</dt>
<dd>An {{domxref("EventHandler")}} that is called whenever the <code>readyState</code> attribute changes.</dd>
<dt id="xmlhttprequest-readystate">{{domxref("XMLHttpRequest.readyState")}} {{readonlyinline}}</dt>
<dd>Returns an <code>unsigned short</code>, the state of the request.</dd>
<dt>{{domxref("XMLHttpRequest.response")}} {{readonlyinline}}</dt>
<dd>Returns an {{jsxref("ArrayBuffer")}}, {{domxref("Blob")}}, {{domxref("Document")}}, JavaScript object, or a {{domxref("DOMString")}}, depending on the value of {{domxref("XMLHttpRequest.responseType")}}, that contains the response entity body.</dd>
<dt id="xmlhttprequest-responsetext">{{domxref("XMLHttpRequest.responseText")}} {{readonlyinline}}</dt>
<dd>Returns a {{domxref("DOMString")}} that contains the response to the request as text, or <code>null</code> if the request was unsuccessful or has not yet been sent.</dd>
<dt id="xmlhttprequest-responsetype">{{domxref("XMLHttpRequest.responseType")}}</dt>
<dd>Is an enumerated value that defines the response type.</dd>
<dt id="xmlhttprequest-responsexml">{{domxref("XMLHttpRequest.responseURL")}} {{readonlyinline}}</dt>
<dd>Returns the serialized URL of the response or the empty string if the URL is null.</dd>
<dt id="xmlhttprequest-responsexml">{{domxref("XMLHttpRequest.responseXML")}} {{readonlyinline}}</dt>
<dd>Returns a {{domxref("Document")}} containing the response to the request, or <code>null</code> if the request was unsuccessful, has not yet been sent, or cannot be parsed as XML or HTML. Not available in workers.</dd>
<dt id="xmlhttprequest-status">{{domxref("XMLHttpRequest.status")}} {{readonlyinline}}</dt>
<dd>Returns an <code>unsigned short</code> with the status of the response of the request.</dd>
<dt id="xmlhttprequest-statustext">{{domxref("XMLHttpRequest.statusText")}} {{readonlyinline}}</dt>
<dd>Returns a {{domxref("DOMString")}} containing the response string returned by the HTTP server. Unlike {{domxref("XMLHttpRequest.status")}}, this includes the entire text of the response message ("<code>200 OK</code>", for example).</dd>
</dl>
<div class="note">
<p><strong>Note:</strong> According to the HTTP/2 specification (<a href="https://http2.github.io/http2-spec/#rfc.section.8.1.2.4">8.1.2.4</a> <a href="https://http2.github.io/http2-spec/#HttpResponse">Response Pseudo-Header Fields</a>), HTTP/2 does not define a way to carry the version or reason phrase that is included in an HTTP/1.1 status line.</p>
</div>
<dl>
<dt id="xmlhttprequest-timeout">{{domxref("XMLHttpRequest.timeout")}}</dt>
<dd>Is an <code>unsigned long</code> representing the number of milliseconds a request can take before automatically being terminated.</dd>
<dt id="xmlhttprequesteventtarget-ontimeout">{{domxref("XMLHttpRequestEventTarget.ontimeout")}}</dt>
<dd>Is an {{domxref("EventHandler")}} that is called whenever the request times out. {{gecko_minversion_inline("12.0")}}</dd>
<dt id="xmlhttprequest-upload">{{domxref("XMLHttpRequest.upload")}} {{readonlyinline}}</dt>
<dd>Is an {{domxref("XMLHttpRequestUpload")}}, representing the upload process.</dd>
<dt id="xmlhttprequest-withcredentials">{{domxref("XMLHttpRequest.withCredentials")}}</dt>
<dd>Is a {{domxref("Boolean")}} that indicates whether or not cross-site <code>Access-Control</code> requests should be made using credentials such as cookies or authorization headers.</dd>
</dl>
<h3 id="Non-standard_properties">Non-standard properties</h3>
<dl>
<dt>{{domxref("XMLHttpRequest.channel")}}{{ReadOnlyInline}}</dt>
<dd>Is a {{Interface("nsIChannel")}}. The channel used by the object when performing the request.</dd>
<dt>{{domxref("XMLHttpRequest.mozAnon")}}{{ReadOnlyInline}}</dt>
<dd>Is a boolean. If true, the request will be sent without cookie and authentication headers.</dd>
<dt>{{domxref("XMLHttpRequest.mozSystem")}}{{ReadOnlyInline}}</dt>
<dd>Is a boolean. If true, the same origin policy will not be enforced on the request.</dd>
<dt>{{domxref("XMLHttpRequest.mozBackgroundRequest")}}</dt>
<dd>Is a boolean. It indicates whether or not the object represents a background service request.</dd>
<dt>{{domxref("XMLHttpRequest.mozResponseArrayBuffer")}}{{gecko_minversion_inline("2.0")}} {{obsolete_inline("6")}} {{ReadOnlyInline}}</dt>
<dd>{{jsxref("ArrayBuffer")}}. The response to the request, as a JavaScript typed array.</dd>
<dt>{{domxref("XMLHttpRequest.multipart")}}{{obsolete_inline("22")}}</dt>
<dd><strong>This Gecko-only feature, a boolean, was removed in Firefox/Gecko 22.</strong> Please use <a href="/en-US/docs/Web/API/Server-sent_events">Server-Sent Events</a>, <a href="/en-US/docs/Web/API/WebSockets_API">Web Sockets</a>, or <code>responseText</code> from progress events instead.</dd>
</dl>
<h3 id="Event_handlers">Event handlers</h3>
<p><code>onreadystatechange</code> as a property of the <code>XMLHttpRequest</code> instance is supported in all browsers.</p>
<p>Since then, a number of additional event handlers have been implemented in various browsers (<code>onload</code>, <code>onerror</code>, <code>onprogress</code>, etc.). See <a href="https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Using_XMLHttpRequest">Using XMLHttpRequest</a>.</p>
<p>More recent browsers, including Firefox, also support listening to the <code>XMLHttpRequest</code> events via standard {{domxref("EventTarget.addEventListener", "addEventListener()")}} APIs in addition to setting <code>on*</code> properties to a handler function.</p>
<h2 id="Methods">Methods</h2>
<dl>
<dt>{{domxref("XMLHttpRequest.abort()")}}</dt>
<dd>Aborts the request if it has already been sent.</dd>
<dt>{{domxref("XMLHttpRequest.getAllResponseHeaders()")}}</dt>
<dd>Returns all the response headers, separated by {{Glossary("CRLF")}}, as a string, or <code>null</code> if no response has been received.</dd>
<dt>{{domxref("XMLHttpRequest.getResponseHeader()")}}</dt>
<dd>Returns the string containing the text of the specified header, or <code>null</code> if either the response has not yet been received or the header doesn't exist in the response.</dd>
<dt>{{domxref("XMLHttpRequest.open()")}}</dt>
<dd>Initializes a request.</dd>
<dt>{{domxref("XMLHttpRequest.overrideMimeType()")}}</dt>
<dd>Overrides the MIME type returned by the server.</dd>
<dt>{{domxref("XMLHttpRequest.send()")}}</dt>
<dd>Sends the request. If the request is asynchronous (which is the default), this method returns as soon as the request is sent.</dd>
<dt>{{domxref("XMLHttpRequest.setRequestHeader()")}}</dt>
<dd>Sets the value of an HTTP request header. You must call <code>setRequestHeader()</code>after <a href="#open"><code>open()</code></a>, but before <code>send()</code>.</dd>
</dl>
<h3 id="Non-standard_methods">Non-standard methods</h3>
<dl>
<dt>{{domxref("XMLHttpRequest.init()")}}</dt>
<dd>Initializes the object for use from C++ code.</dd>
</dl>
<div class="warning"><strong>Warning:</strong> This method must <em>not</em> be called from JavaScript.</div>
<dl>
<dt>{{domxref("XMLHttpRequest.openRequest()")}}</dt>
<dd>Initializes a request. This method is to be used from native code; to initialize a request from JavaScript code, use <a class="internal" href="/en-US/docs/Mozilla/Tech/XPCOM/Reference/Interface/nsIXMLHttpRequest#open()"><code>open()</code></a> instead. See the documentation for <code>open()</code>.</dd>
<dt>{{domxref("XMLHttpRequest.sendAsBinary()")}}{{deprecated_inline()}}</dt>
<dd>A variant of the <code>send()</code> method that sends binary data.</dd>
</dl>
<h2 id="Events">Events</h2>
<dl>
<dt>{{domxref("XMLHttpRequest/abort_event", "abort")}}</dt>
<dd>Fired when a request has been aborted, for example because the program called {{domxref("XMLHttpRequest.abort()")}}.<br>
Also available via the {{domxref("XMLHttpRequestEventTarget/onabort", "onabort")}} property.</dd>
<dt>{{domxref("XMLHttpRequest/error_event", "error")}}</dt>
<dd>Fired when the request encountered an error.<br>
Also available via the {{domxref("XMLHttpRequestEventTarget/onerror", "onerror")}} property.</dd>
<dt>{{domxref("XMLHttpRequest/load_event", "load")}}</dt>
<dd>Fired when an {{domxref("XMLHttpRequest")}} transaction completes successfully.<br>
Also available via the {{domxref("XMLHttpRequestEventTarget/onload", "onload")}} property.</dd>
<dt>{{domxref("XMLHttpRequest/loadend_event", "loadend")}}</dt>
<dd>Fired when a request has completed, whether successfully (after {{domxref("XMLHttpRequest/load_event", "load")}}) or unsuccessfully (after {{domxref("XMLHttpRequest/abort_event", "abort")}} or {{domxref("XMLHttpRequest/error_event", "error")}}).<br>
Also available via the {{domxref("XMLHttpRequestEventTarget/onloadend", "onloadend")}} property.</dd>
<dt>{{domxref("XMLHttpRequest/loadstart_event", "loadstart")}}</dt>
<dd>Fired when a request has started to load data.<br>
Also available via the {{domxref("XMLHttpRequestEventTarget/onloadstart", "onloadstart")}} property.</dd>
<dt>{{domxref("XMLHttpRequest/progress_event", "progress")}}</dt>
<dd>Fired periodically when a request receives more data.<br>
Also available via the {{domxref("XMLHttpRequestEventTarget/onprogress", "onprogress")}} property.</dd>
<dt>{{domxref("XMLHttpRequest/timeout_event", "timeout")}}</dt>
<dd>Fired when progress is terminated due to preset time expiring.<br>
Also available via the {{domxref("XMLHttpRequestEventTarget/ontimeout", "ontimeout")}} property.</dd>
</dl>
<h2 id="Specifications">Specifications</h2>
<table class="standard-table">
<thead>
<tr>
<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
</tr>
</thead>
<tbody>
<tr>
<td>{{SpecName('XMLHttpRequest')}}</td>
<td>{{Spec2('XMLHttpRequest')}}</td>
<td>Live standard, latest version</td>
</tr>
</tbody>
</table>
<h2 id="Browser_compatibility">Browser compatibility</h2>
<div>{{Compat("api.XMLHttpRequest")}}</div>
<h2 id="See_also">See also</h2>
<ul>
<li>{{domxref("XMLSerializer")}}: Serializing a DOM tree into XML</li>
<li>MDN tutorials covering <code>XMLHttpRequest</code>:
<ul>
<li><a href="/en-US/docs/AJAX/Getting_Started">Ajax — Getting Started</a></li>
<li><a href="/en-US/docs/Web/API/XMLHttpRequest/Using_XMLHttpRequest">Using XMLHttpRequest</a></li>
<li><a href="/en-US/docs/Web/API/XMLHttpRequest/HTML_in_XMLHttpRequest">HTML in XMLHttpRequest</a></li>
<li><a href="/en-US/docs/Web/API/Fetch_API" title="Fetch API">Fetch API</a></li>
</ul>
</li>
<li><a class="external" href="http://www.html5rocks.com/en/tutorials/file/xhr2/">HTML5 Rocks — New Tricks in XMLHttpRequest2</a></li>
<li>Feature-Policy directive {{httpheader("Feature-Policy/sync-xhr", "sync-xhr")}}</li>
</ul>
|
