---
title: HTMLFormElement
slug: Web/API/HTMLFormElement
translation_of: Web/API/HTMLFormElement
---
<div>{{APIRef("HTML DOM")}}</div>
<p><strong><code>HTMLFormElement</code></strong> 介面提供了建立及修改 {{HTMLElement("form")}} 元素的方法。<br>
<strong>document.forms</strong> - returns an array of HTMLFormElement objects referencing all forms on the page.<br>
<strong>document.forms[index] </strong>- returns an HTMLFormElement object referencing the form at the specified index.<br>
<strong>document.forms['id'] </strong>- returns an HTMLFormElement object referencing the form with the specified id.<br>
<strong>document.forms['name'] </strong>- returns an HTMLFormElement object referencing the form with the specified name.</p>
<p>{{InheritanceDiagram(600,120)}}</p>
<h2 id="屬性">屬性</h2>
<p><em>This interface also inherits properties from its parent, {{domxref("HTMLElement")}}.</em></p>
<dl>
<dt>{{domxref("HTMLFormElement.elements")}}{{ReadOnlyInline}}</dt>
<dd>A {{domxref("HTMLFormControlsCollection")}} holding all form controls belonging to this form element.</dd>
<dt>{{domxref("HTMLFormElement.length")}}{{ReadOnlyInline}}</dt>
<dd>A <code>long</code> reflecting the number of controls in the form.</dd>
<dt>{{domxref("HTMLFormElement.name")}}</dt>
<dd>A {{domxref("DOMString")}} reflecting the value of the form's {{ htmlattrxref("name", "form") }} HTML attribute, containing the name of the form.</dd>
<dt>{{domxref("HTMLFormElement.method")}}</dt>
<dd>A {{domxref("DOMString")}} reflecting the value of the form's {{ htmlattrxref("method", "form") }} HTML attribute, indicating the HTTP method used to submit the form. Only specified values can be set.</dd>
<dt>{{domxref("HTMLFormElement.target")}}</dt>
<dd>A {{domxref("DOMString")}} reflecting the value of the form's {{ htmlattrxref("target", "form") }} HTML attribute, indicating where to display the results received from submitting the form.</dd>
<dt>{{domxref("HTMLFormElement.action")}}</dt>
<dd>A {{domxref("DOMString")}} reflecting the value of the form's {{ htmlattrxref("action", "form") }} HTML attribute, containing the URI of a program that processes the information submitted by the form.</dd>
<dt>{{domxref("HTMLFormElement.encoding")}} or {{domxref("HTMLFormElement.enctype")}}</dt>
<dd>A {{domxref("DOMString")}} reflecting the value of the form's {{ htmlattrxref("enctype", "form") }} HTML attribute, indicating the type of content that is used to transmit the form to the server. Only specified values can be set. The two methods are synonyms.</dd>
<dt>{{domxref("HTMLFormElement.acceptCharset")}}</dt>
<dd>A {{domxref("DOMString")}} reflecting the value of the form's {{ htmlattrxref("accept-charset", "form") }} HTML attribute, representing the character encoding that the server accepts.</dd>
<dt>{{domxref("HTMLFormElement.autocomplete")}}</dt>
<dd>A {{domxref("DOMString")}} reflecting the value of the form's {{ htmlattrxref("autocomplete", "form") }} HTML attribute, indicating whether the controls in this form can have their values automatically populated by the browser.</dd>
<dt>{{domxref("HTMLFormElement.noValidate")}}</dt>
<dd>A {{jsxref("Boolean")}} reflecting the value of the form's {{ htmlattrxref("novalidate", "form") }} HTML attribute, indicating whether the form should not be validated.</dd>
</dl>
<h2 id="方法">方法</h2>
<p><em>This interface also inherits methods from its parent, {{domxref("HTMLElement")}}.</em></p>
<dl>
<dt>{{domxref("HTMLFormElement.submit()")}}</dt>
<dd>Submits the form to the server.</dd>
<dt>{{domxref("HTMLFormElement.reset()")}}</dt>
<dd>Resets the form to its initial state.</dd>
<dt>{{domxref("HTMLFormElement.checkValidity()")}}</dt>
<dd>Returns <code>true</code> if the element's child controls are subject to constraint validation and satisfy those contraints; returns <code>false</code> if some controls do not satisfy their constraints. Fires an event named {{event("invalid")}} at any control that does not satisfy its constraints; such controls are considered invalid if the event is not canceled. It is up to the programmer to decide how to respond to <code>false</code>.</dd>
<dt>{{domxref("HTMLFormElement.reportValidity()")}}</dt>
<dd>Returns <code>true</code> if the element's child controls satisfy their validation constraints. When <code>false</code> is returned, cancelable {{Event("invalid")}} events are fired for each invalid child and validation problems are reported to the user.</dd>
<dt>{{domxref("HTMLFormElement.requestAutocomplete()")}}</dt>
<dd>Triggers a native browser interface to assist the user in completing the fields which have an <a href="https://html.spec.whatwg.org/#autofill-field-name">autofill field name</a> value that is not <code>off</code> or <code>on</code>. The form will receive an event once the user has finished with the interface, the event will either be {{event("autocomplete")}} when the fields have been filled or {{event("autocompleteerror")}} when there was a problem.</dd>
</dl>
<h2 id="範例">範例</h2>
<p>Create a new form element, modify its attributes and submit it:</p>
<pre class="brush: js">var f = document.createElement("form");// Create a form
document.body.appendChild(f); // Add it to the document body
f.action = "/cgi-bin/some.cgi"; // Add action and method attributes
f.method = "POST"
f.submit(); // Call the form's submit method
</pre>
<p>Extract information from a form element and set some of its attributes:</p>
<pre class="brush: html"><form name="formA" id="formA" action="/cgi-bin/test" method="POST">
<p>Click "Info" for form details; "Set" to change settings.</p>
<p>
<input type="button" value="info" onclick="getFormInfo();">
<input type="button" value="set" onclick="setFormInfo(this.form);">
<input type="reset" value="reset"><br>
<textarea id="tex" style="height:15em; width:20em"></textarea>
</p>
</form>
<script type="text/javascript">
function getFormInfo(){
var info;
var f = document.forms["formA"]; //Get a reference to the form via id.
info = "elements: " + f.elements + "\n"
+ "length: " + f.length + "\n"
+ "name: " + f.name + "\n"
+ "charset: " + f.acceptCharset+ "\n"
+ "action: " + f.action + "\n"
+ "enctype: " + f.enctype + "\n"
+ "encoding: " + f.encoding + "\n"
+ "method: " + f.method + "\n"
+ "target: " + f.target;
document.forms["formA"].elements['tex'].value = info;
}
function setFormInfo(f){ //Argument is a reference to the form.
f.method = "GET";
f.action = "/cgi-bin/evil_executable.cgi";
f.name = "totally_new";
}
</script>
</pre>
<p>Submit a form in a <a href="/en-US/docs/Web/API/Window/open">popup window</a>:</p>
<pre class="brush: html"><!doctype html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>MDN Example</title>
<script type="text/javascript">
function popupSend (oFormElement) {
if (oFormElement.method && oFormElement.method.toLowerCase() !== "get") {
console.error("This script supports the GET method only.");
return;
}
var oField, sFieldType, nFile, sSearch = "";
for (var nItem = 0; nItem < oFormElement.elements.length; nItem++) {
oField = oFormElement.elements[nItem];
if (!oField.hasAttribute("name")) { continue; }
sFieldType = oField.nodeName.toUpperCase() === "INPUT" ? oField.getAttribute("type").toUpperCase() : "TEXT";
if (sFieldType === "FILE") {
for (nFile = 0; nFile < oField.files.length; sSearch += "&" + escape(oField.name) + "=" + escape(oField.files[nFile++].name));
} else if ((sFieldType !== "RADIO" && sFieldType !== "CHECKBOX") || oField.checked) {
sSearch += "&" + escape(oField.name) + "=" + escape(oField.value);
}
}
open(oFormElement.action.replace(/(?:\?.*)?$/, sSearch.replace(/^&/, "?")), "submit-" + (oFormElement.name || Math.floor(Math.random() * 1e6)), "resizable=yes,scrollbars=yes,status=yes");
}
</script>
</head>
<body>
<form name="yourForm" action="test.php" method="get" onsubmit="popupSend(this); return false;">
<p>First name: <input type="text" name="firstname" /><br />
Last name: <input type="text" name="lastname" /><br />
Password: <input type="password" name="pwd" /><br />
<input type="radio" name="sex" value="male" /> Male <input type="radio" name="sex" value="female" /> Female</p>
<p><input type="checkbox" name="vehicle" value="Bike" />I have a bike<br />
<input type="checkbox" name="vehicle" value="Car" />I have a car</p>
<p><input type="submit" value="Submit" /></p>
</form>
</body>
</html></pre>
<h3 id="使用_XMLHttpRequest_提交表單及上傳檔案">使用 <code>XMLHttpRequest</code> 提交表單及上傳檔案</h3>
<p>If you want to know how to serialize and submit a form using the {{domxref("XMLHttpRequest")}} API, please read <a href="/en-US/docs/DOM/XMLHttpRequest/Using_XMLHttpRequest#Submitting_forms_and_uploading_files">this paragraph</a>.</p>
<h2 id="規範">規範</h2>
<table class="standard-table">
<tbody>
<tr>
<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
</tr>
<tr>
<td>{{SpecName('HTML WHATWG', "forms.html#the-form-element", "HTMLFormElement")}}</td>
<td>{{Spec2('HTML WHATWG')}}</td>
<td>The following method has been added: <code>requestAutocomplete()</code>.</td>
</tr>
<tr>
<td>{{SpecName('HTML5 W3C', "forms.html#the-form-element", "HTMLFormElement")}}</td>
<td>{{Spec2('HTML5 W3C')}}</td>
<td>The elements properties returns an {{domxref("HTMLFormControlsCollection")}} instead of a raw {{domxref("HTMLCollection")}}. This is mainly a technical change. The following method has been added: <code>checkValidity()</code>. The following properties have been added: <code>autocomplete</code>, <code>noValidate</code>, and <code>encoding</code>.</td>
</tr>
<tr>
<td>{{SpecName('DOM2 HTML', 'html.html#ID-40002357', 'HTMLFormElement')}}</td>
<td>{{Spec2('DOM2 HTML')}}</td>
<td>No change</td>
</tr>
<tr>
<td>{{SpecName('DOM1', 'level-one-html.html#ID-40002357', 'HTMLFormElement')}}</td>
<td>{{Spec2('DOM1')}}</td>
<td>Initial definition</td>
</tr>
</tbody>
</table>
<h2 id="瀏覽器相容性">瀏覽器相容性</h2>
<p>{{CompatibilityTable}}</p>
<div id="compat-desktop">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Chrome</th>
<th>Edge</th>
<th>Firefox (Gecko)</th>
<th>Internet Explorer</th>
<th>Opera</th>
<th>Safari (WebKit)</th>
</tr>
<tr>
<td>Basic support</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatGeckoDesktop(1.0)}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
</tr>
</tbody>
</table>
</div>
<div id="compat-mobile">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Android</th>
<th>Edge</th>
<th>Firefox Mobile (Gecko)</th>
<th>IE Phone</th>
<th>Opera Mobile</th>
<th>Safari Mobile</th>
</tr>
<tr>
<td>Basic support</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatGeckoMobile(1.0)}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
</tr>
</tbody>
</table>
</div>
<h2 id="參見">參見</h2>
<ul>
<li>The HTML element implementing this interface: {{ HTMLElement("form") }}.</li>
</ul>