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---
title: String.prototype.toString()
slug: Web/JavaScript/Reference/Global_Objects/String/toString
translation_of: Web/JavaScript/Reference/Global_Objects/String/toString
---
<div>{{JSRef("Global_Objects", "String")}}</div>
<h2 id="Summary" name="Summary">概述</h2>
<p><code><strong>toString()</strong></code> 方法返回指定对象的字符串形式。</p>
<h2 id="Syntax" name="Syntax">语法</h2>
<pre class="syntaxbox"><code><em>str</em>.toString()</code>
</pre>
<h3 id="返回值">返回值</h3>
<p>一个表示调用对象的字符串。</p>
<h2 id="Description" name="Description">描述</h2>
<p><code>String</code> 对象覆盖了{{jsxref("Global_Objects/Object", "Object")}} 对象的 <code>toString</code> 方法；并没有继承 {{jsxref("Object.toString()")}}。对于 <code>String</code> 对象，<code>toString</code> 方法返回该对象的字符串形式，和 {{jsxref("String.prototype.valueOf()")}} 方法返回值一样。</p>
<h2 id="Examples" name="Examples">示例</h2>
<h3 id="Example_Using_toString" name="Example:_Using_toString">例子：使用 <code>toString</code></h3>
<p>下例输出一个字符串对象（String object）的字符串值：</p>
<pre class="brush:js">var x = new String("Hello world");
alert(x.toString()) // 输出 "Hello world"</pre>
<h2 id="规范">规范</h2>
<table>
<tbody>
<tr>
<th scope="col">Specification</th>
<th scope="col">Status</th>
<th scope="col">Comment</th>
</tr>
<tr>
<td>{{SpecName('ES3')}}</td>
<td>{{Spec2('ES3')}}</td>
<td>Initial definition. Implemented in JavaScript 1.1.</td>
</tr>
<tr>
<td>{{SpecName('ES5.1', '#sec-15.5.4.2', 'String.prototype.toString')}}</td>
<td>{{Spec2('ES5.1')}}</td>
<td></td>
</tr>
<tr>
<td>{{SpecName('ES6', '#sec-string.prototype.tostring', 'String.prototype.toString')}}</td>
<td>{{Spec2('ES6')}}</td>
<td></td>
</tr>
<tr>
<td>{{SpecName('ESDraft', '#sec-string.prototype.tostring', 'String.prototype.toString')}}</td>
<td>{{Spec2('ESDraft')}}</td>
<td></td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<p>{{ CompatibilityTable() }}</p>
<div>
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Chrome</th>
<th>Firefox (Gecko)</th>
<th>Internet Explorer</th>
<th>Opera</th>
<th>Safari</th>
</tr>
<tr>
<td>Basic support</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
</tr>
</tbody>
</table>
</div>
<div>
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Android</th>
<th>Chrome for Android</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>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
<td>{{ CompatVersionUnknown() }}</td>
</tr>
</tbody>
</table>
</div>
<h2 id="See_also" name="See_also">相关链接</h2>
<ul>
<li>{{jsxref("Object.prototype.toSource()")}}</li>
<li>{{jsxref("String.prototype.valueOf()")}}</li>
</ul>
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