---
title: XMLHttpRequest
slug: Web/API/XMLHttpRequest
tags:
  - AJAX
  - API
  - HTTP
  - Interface
  - Referencia
  - Web
  - XHR
translation_of: Web/API/XMLHttpRequest
---
<div>{{APIRef("XMLHttpRequest")}}</div>

<p><span class="seoSummary">Utilize os objetos <code>XMLHttpRequest</code> (XHR) para interagir com os servidores. Pode obter os dados de um URL sem ter que recarregar toda a página. Isto permite que uma página da Web atualize apenas parte da mesma, </span> sem interromper o que o utilizador está a fazer<span class="seoSummary">.</span> <code>XMLHttpRequest</code> é totalmente utilizado na programação <a href="/pt-PT/docs/Web/Guide/AJAX">Ajax</a>.</p>

<p>{{InheritanceDiagram}}</p>

<h5 id="História">História</h5>

<p><code>XMLHttpRequest</code> was originally designed by Microsoft around 1999 and later adopted by Mozilla, Apple, and Google. Since October 2014, it has been <a class="external" href="https://xhr.spec.whatwg.org/">standardized at the <abbr title="Web Hypertext Application Technology Working Group">WHATWG</abbr></a>, <a href="https://fetch.spec.whatwg.org/">together</a> with the new promise-based {{domxref("WindowOrWorkerGlobalScope.fetch()", "fetch()")}} method.</p>

<p>Despite its name, <code>XMLHttpRequest</code> can be used to retrieve any type of data, not just XML, and it supports protocols other than <a href="/en-US/docs/Web/HTTP">HTTP</a> (including <code>file</code> and <code>ftp</code>).</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="Propriedades">Propriedades</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 {{domxref("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>Nota:</strong> via 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="Proriedades_não_padrão">Proriedades não padrão</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>Is an <a href="/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer"><code>ArrayBuffer</code></a>. 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="Manipuladores_de_evento">Manipuladores de evento</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 were implemented in various browsers (<code>onload</code>, <code>onerror</code>, <code>onprogress</code>, etc.). These are supported in Firefox. In particular, see <code><a href="https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Reference/Interface/nsIXMLHttpRequestEventTarget" title="">nsIXMLHttpRequestEventTarget</a></code> and <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 <code><a href="https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/addEventListener">addEventListener</a></code> APIs in addition to setting <code>on*</code> properties to a handler function.</p>

<h2 id="Métodos">Métodos</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 <a href="https://developer.mozilla.org/en-US/docs/Glossary/CRLF">CRLF</a>, 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. This method is to be used from JavaScript code; to initialize a request from native code, use <a class="internal" href="/en-US/docs/Mozilla/Tech/XPCOM/Reference/Interface/nsIXMLHttpRequest#openRequest()"><code>openRequest()</code></a> instead.</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="Métodos_não_padrão">Métodos não padrão</h3>

<dl>
 <dt>{{domxref("XMLHttpRequest.init()")}}</dt>
 <dd>Initializes the object for use from C++ code.</dd>
</dl>

<div class="warning"><strong>Aviso:</strong> este método <strong>não </strong>deve ser chamado do 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="Especificações">Especificações</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Especificação</th>
   <th scope="col">Estado</th>
   <th scope="col">Comentário</th>
  </tr>
  <tr>
   <td>{{SpecName('XMLHttpRequest')}}</td>
   <td>{{Spec2('XMLHttpRequest')}}</td>
   <td>Live standard, latest version</td>
  </tr>
 </tbody>
</table>

<h2 id="Compatibilidade_de_navegador">Compatibilidade de navegador</h2>



<div>{{Compat("api.XMLHttpRequest")}}</div>

<h2 id="Consulte_também">Consulte também</h2>

<ul>
 <li>Tutoriais da MDN abrangendo XMLHttpRequest:
  <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/FormData"><code>FormData</code></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><code>Chrome scope availability</code> — how to access XMLHttpRequest from JSM modules etc., which do not have access to DOM
  <ul>
   <li><a href="/en-US/docs/Mozilla/Tech/XPCOM/Language_Bindings/Components.utils.importGlobalProperties">Components.utils.importGlobalProperties</a></li>
   <li><a href="/en-US/docs/Mozilla/Tech/XPCOM/Reference/Interface/nsIXMLHttpRequest">nsIXMLHttpRequest</a></li>
  </ul>
 </li>
</ul>