---
title: HTMLCanvasElement.width
slug: Web/API/HTMLCanvasElement/width
translation_of: Web/API/HTMLCanvasElement/width
---
<div>
<div>
<div>{{APIRef("Canvas API")}}</div>
</div>
</div>

<p><strong><code><span>HTMLCanvasElement.width </span></code></strong>属性是一个对应 {{HTMLElement("canvas")}} 元素 CSS 像素 {{htmlattrxref("width", "canvas")}} 的正整数. 当这个属性没有指定时, 或者被赋予一个不合法的值, 比如一个负值, 默认使用 300.</p>

<p>这是其中之一，另一个是 {{domxref("HTMLCanvasElement.height")}}, 它们控制了 canvas 的大小尺寸.</p>

<h2 id="Syntax" name="Syntax">语法</h2>

<pre class="syntaxbox"><var>var <em>pxl</em> = <em>canvas</em></var>.width;
<em>canvas</em>.width = <em>pxl</em>;
</pre>

<h2 id="示例">示例</h2>

<p>有这样一个 {{HTMLElement("canvas")}} 元素:</p>

<pre class="brush: html">&lt;canvas id="canvas" width="300" height="300"&gt;&lt;/canvas&gt;
</pre>

<p>你能够通过下面的代码得到 canvas 的宽度:</p>

<pre class="brush: js">var canvas = document.getElementById('canvas');
console.log(canvas.width); // 300
</pre>

<h2 id="规范">规范</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', "scripting.html#attr-canvas-width", "HTMLCanvasElement.width")}}</td>
   <td>{{Spec2('HTML WHATWG')}}</td>
   <td>No change since the latest snapshot, {{SpecName('HTML5 W3C')}}</td>
  </tr>
  <tr>
   <td>{{SpecName('HTML5.1', "scripting-1.html#attr-canvas-width", "HTMLCanvasElement.width")}}</td>
   <td>{{Spec2('HTML5.1')}}</td>
   <td> </td>
  </tr>
  <tr>
   <td>{{SpecName('HTML5 W3C', "scripting-1.html#attr-canvas-width", "HTMLCanvasElement.width")}}</td>
   <td>{{Spec2('HTML5 W3C')}}</td>
   <td>Snapshot of the {{SpecName('HTML WHATWG')}} containing the initial definition.</td>
  </tr>
 </tbody>
</table>

<h2 id="浏览器兼容性">浏览器兼容性</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</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{ CompatChrome(4) }}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{ CompatGeckoDesktop("1.9.2") }}</td>
   <td>{{ CompatIE(9) }}</td>
   <td>{{ CompatOpera(9) }}</td>
   <td>{{ CompatSafari(3.1) }}</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Chrome for Android</th>
   <th>Edge</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{ CompatVersionUnknown() }}</td>
   <td>{{ CompatVersionUnknown() }}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{ CompatGeckoMobile("1.9.2") }}</td>
   <td>{{ CompatVersionUnknown() }}</td>
   <td>{{ CompatVersionUnknown() }}</td>
   <td>{{ CompatVersionUnknown() }}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="See_Also" name="See_Also">查看更多</h2>

<ul>
 <li>The interface defining it, {{domxref("HTMLCanvasElement")}}.</li>
 <li>另一个控制 canvas 大小的属性, {{domxref("HTMLCanvasElement.height")}}.</li>
</ul>