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136 lines
5.6 KiB
HTML
136 lines
5.6 KiB
HTML
<article id="wikiArticle">
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<div>
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</div>
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<h2 id="Summary" name="Summary">概述</h2>
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<p><code><strong>toString()</strong></code> 方法返回一个指定的错误对象（Error object）的字符串表示。</p>
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<h2 id="Syntax" name="Syntax">语法</h2>
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<pre><code class="language-javascript"><code><em>e</em>.toString();</code></code></pre>
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<h2 id="Description" name="Description">描述</h2>
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<p><a href="Reference/Global_Objects/Error" title="通过Error的构造器可以创建一个错误对象。当运行时错误产生时，Error的实例对象会被抛出。Error对象也可用于用户自定义的异常的基础对象。下面列出了各种内建的标准错误类型。"><code>Error</code></a> 对象覆盖了 <a href="Reference/Global_Objects/Object/toString" title="toString() 方法返回一个表示该对象的字符串。"><code>Object.prototype.toString()</code></a> 方法。该方法实现如下：（假定 <code>Object</code> 和 <code>String</code> 没有被更改）：</p>
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<pre><code class="language-js">Error.prototype.toString = function()
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{
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"use strict";
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var obj = Object(this);
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if (obj !== this)
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throw new TypeError();
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var name = this.name;
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name = (name === undefined) ? "Error" : String(name);
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var msg = this.message;
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msg = (msg === undefined) ? "" : String(msg);
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if (name === "")
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return msg;
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if (msg === "")
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return name;
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return name + ": " + msg;
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};
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</code></pre>
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<h2 id="Example" name="Example">示例</h2>
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<pre><code class="language-js">var e = new Error("fatal error");
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print(e.toString()); // "Error: fatal error"
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e.name = undefined;
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print(e.toString()); // "Error: fatal error"
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e.name = "";
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print(e.toString()); // "fatal error"
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e.message = undefined;
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print(e.toString()); // "Error"
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e.name = "hello";
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print(e.toString()); // "hello"
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</code></pre>
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<h2 id="规范">规范</h2>
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<table class="standard-table">
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<tbody>
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<tr>
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<th scope="col">规范版本</th>
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<th scope="col">规范状态</th>
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<th scope="col">注解</th>
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</tr>
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<tr>
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<td>ECMAScript 1st Edition.</td>
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<td>Standard</td>
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<td>Initial definition.<br/>
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Implemented in JavaScript 1.1</td>
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</tr>
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<tr>
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<td><a class="external" href="https://www.ecma-international.org/ecma-262/5.1/#sec-15.11.4.4" hreflang="en" lang="en" rel="noopener">ECMAScript 5.1 (ECMA-262)<br/><small lang="zh-CN">Error.prototype.toString</small></a></td>
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<td><span class="spec-Standard">Standard</span></td>
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<td> </td>
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</tr>
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<tr>
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<td><a class="external" href="https://www.ecma-international.org/ecma-262/6.0/#sec-error.prototype.tostring" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">Error.prototype.toString</small></a></td>
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<td><span class="spec-Standard">Standard</span></td>
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<td> </td>
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</tr>
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</tbody>
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</table>
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<h2 id="浏览器兼容性">浏览器兼容性</h2>
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<p></p><div class="blockIndicator warning"><strong><a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">We're converting our compatibility data into a machine-readable JSON format</a></strong>.
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This compatibility table still uses the old format,
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because we haven't yet converted the data it contains.
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<strong><a class="new" href="/zh-CN/docs/MDN/Contribute/Structures/Compatibility_tables" rel="nofollow">Find out how you can help!</a></strong></div>
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<div class="htab">
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<a id="AutoCompatibilityTable" name="AutoCompatibilityTable"></a>
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<ul>
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<li class="selected"><a>Desktop</a></li>
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<li><a>Mobile</a></li>
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</ul>
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</div><p></p>
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<div id="compat-desktop">
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<table class="compat-table">
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<tbody>
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<tr>
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<th>Feature</th>
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<th>Chrome</th>
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<th>Firefox (Gecko)</th>
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<th>Internet Explorer</th>
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<th>Opera</th>
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<th>Safari</th>
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</tr>
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<tr>
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<td>Basic support</td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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</tr>
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</tbody>
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</table>
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</div>
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<div id="compat-mobile">
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<table class="compat-table">
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<tbody>
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<tr>
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<th>Feature</th>
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<th>Android</th>
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<th>Chrome for Android</th>
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<th>Firefox Mobile (Gecko)</th>
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<th>IE Mobile</th>
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<th>Opera Mobile</th>
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<th>Safari Mobile</th>
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</tr>
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<tr>
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<td>Basic support</td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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<td><span style="color: #888;" title="Please update this with the earliest version of support.">(Yes)</span></td>
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</tr>
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</tbody>
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</table>
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</div>
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<h2 id="See_also" name="See_also">相关链接</h2>
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<ul>
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<li><a href="Reference/Global_Objects/Error/toSource" title="toSource() 方法返回可以计算出到相同错误的代码。"><code>Error.prototype.toSource()</code></a></li>
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</ul>
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</article> |