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117 lines
4.3 KiB
HTML
117 lines
4.3 KiB
HTML
<article id="wikiArticle">
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<div></div>
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<p><strong><code>Number.EPSILON</code></strong> 属性表示 1 与<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>可表示的大于 1 的最小的浮点数之间的差值。</p>
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<p>你不必创建一个 <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> 对象来访问这个静态属性(直接使用 <code>Number.EPSILON</code>)。</p>
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<div><table class="standard-table">
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<thead>
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<tr>
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<th class="header" colspan="2"><code>Number.EPSILON</code> 属性的属性特性:</th>
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</tr>
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</thead>
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<tbody>
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<tr>
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<td>writable</td>
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<td>false</td>
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</tr>
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<tr>
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<td>enumerable</td>
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<td>false</td>
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</tr>
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<tr>
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<td>configurable</td>
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<td>false</td>
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</tr>
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</tbody>
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</table></div>
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<h2 id="描述">描述</h2>
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<p><code>EPSILON</code> 属性的值接近于 <code>2.2204460492503130808472633361816E-16</code>,或者 <code>2<sup>-52。</sup></code></p>
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<h2 id="示例">示例</h2>
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<h3 id="测试是否相等">测试是否相等</h3>
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<pre><code class="language-javascript">x = 0.2;
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y = 0.3;
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z = 0.1;
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equal = (Math.abs(x - y + z) < Number.EPSILON);
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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">Specification</th>
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<th scope="col">Status</th>
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<th scope="col">Comment</th>
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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.epsilon" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">Number.EPSILON</small></a></td>
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<td><span class="spec-Standard">Standard</span></td>
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<td>最初定义</td>
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</tr>
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<tr>
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<td><a class="external" href="https://tc39.github.io/ecma262/#sec-number.epsilon" hreflang="en" lang="en" rel="noopener">ECMAScript Latest Draft (ECMA-262)<br/><small lang="zh-CN">Number.EPSILON</small></a></td>
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<td><span class="spec-Draft">Draft</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><a href="/en-US/Firefox/Releases/25" title="Released on 2013-10-29.">25.0</a> (25.0)</td>
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<td><span style="color: #f00;">未实现</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>9</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: #f00;">未实现</span></td>
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<td><span style="color: #f00;">未实现</span></td>
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<td>25.0 (25.0)</td>
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<td><span style="color: #f00;">未实现</span></td>
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<td><span style="color: #f00;">未实现</span></td>
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<td>9</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="相关链接">相关链接</h2>
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<ul>
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<li><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></li>
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</ul>
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</article> |