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106 lines
4.8 KiB
HTML
106 lines
4.8 KiB
HTML
<article id="wikiArticle">
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<div></div>
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<h2 id="Summary" name="Summary">概述</h2>
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<p><strong><code>valueOf()</code></strong> 方法返回一个被 <a href="Reference/Global_Objects/Number" title="JavaScript 的 Number 对象是经过封装的能让你处理数字值的对象。Number 对象由 Number() 构造器创建。"><code>Number</code></a> 对象包装的原始值。</p>
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<h2 id="Syntax" name="Syntax">语法</h2>
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<pre><code class="language-javascript"><code><var>numObj</var>.valueOf()</code></code></pre>
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<h3 id="Parameters" name="Parameters">返回值</h3>
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<p>表示指定 <a href="Reference/Global_Objects/Number" title="JavaScript 的 Number 对象是经过封装的能让你处理数字值的对象。Number 对象由 Number() 构造器创建。"><code>Number</code></a> 对象的原始值的数字</p>
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<h2 id="Description" name="Description">描述</h2>
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<p>该方法通常是由 JavaScript 引擎在内部隐式调用的，而不是由用户在代码中显式调用的。</p>
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<h2 id="Examples" name="Examples">示例</h2>
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<pre><code class="language-javascript">var numObj = new Number(10);
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console.log(typeof numObj); // object
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var num = numObj.valueOf();
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console.log(num); // 10
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console.log(typeof num); // number
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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">规范名称</th>
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<th scope="col">规范状态</th>
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<th scope="col">备注</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> </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-15.7.4.4" hreflang="en" lang="en" rel="noopener">ECMAScript 5.1 (ECMA-262)<br/><small lang="zh-CN">Number.prototype.valueOf</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-number.prototype.valueof" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">Number.prototype.valueOf</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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<div><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></div>
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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/Number/toSource" title="toSource() 方法返回该对象源码的字符串表示。"><code>Number.prototype.toSource()</code></a></li>
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</ul>
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</article> |