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author | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
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committer | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
commit | 33058f2b292b3a581333bdfb21b8f671898c5060 (patch) | |
tree | 51c3e392513ec574331b2d3f85c394445ea803c6 /files/zh-cn/web/javascript/reference/global_objects/number/epsilon | |
parent | 8b66d724f7caf0157093fb09cfec8fbd0c6ad50a (diff) | |
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diff --git a/files/zh-cn/web/javascript/reference/global_objects/number/epsilon/index.html b/files/zh-cn/web/javascript/reference/global_objects/number/epsilon/index.html new file mode 100644 index 0000000000..fea6ee1bb8 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/number/epsilon/index.html @@ -0,0 +1,114 @@ +--- +title: Number.EPSILON +slug: Web/JavaScript/Reference/Global_Objects/Number/EPSILON +translation_of: Web/JavaScript/Reference/Global_Objects/Number/EPSILON +--- +<div>{{JSRef}}</div> + +<p><strong><code>Number.EPSILON</code></strong> 属性表示 1 与{{jsxref("Number")}}可表示的大于 1 的最小的浮点数之间的差值。</p> + +<p>你不必创建一个 {{jsxref("Number")}} 对象来访问这个静态属性(直接使用 <code>Number.EPSILON</code>)。</p> + +<div>{{js_property_attributes(0, 0, 0)}}</div> + +<h2 id="描述">描述</h2> + +<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> + +<h2 id="示例">示例</h2> + +<h3 id="测试是否相等">测试是否相等</h3> + +<pre class="brush: js">x = 0.2; +y = 0.3; +z = 0.1; +equal = (Math.abs(x - y + z) < Number.EPSILON); +</pre> + +<h2 id="Polyfill">Polyfill</h2> + +<pre><code>if (Number.EPSILON === undefined) { + Number.EPSILON = Math.pow(2, -52); +}</code></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('ES6', '#sec-number.epsilon', 'Number.EPSILON')}}</td> + <td>{{Spec2('ES6')}}</td> + <td>最初定义</td> + </tr> + <tr> + <td>{{SpecName('ESDraft', '#sec-number.epsilon', 'Number.EPSILON')}}</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> + +<div>{{CompatibilityTable}}</div> + +<div id="compat-desktop"> +<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>{{CompatGeckoDesktop("25.0")}}</td> + <td>{{CompatNo}}</td> + <td>{{CompatVersionUnknown}}</td> + <td>9</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>Firefox Mobile (Gecko)</th> + <th>IE Mobile</th> + <th>Opera Mobile</th> + <th>Safari Mobile</th> + </tr> + <tr> + <td>Basic support</td> + <td>{{CompatNo}}</td> + <td>{{CompatNo}}</td> + <td>{{CompatGeckoMobile("25.0")}}</td> + <td>{{CompatNo}}</td> + <td>{{CompatNo}}</td> + <td>9</td> + </tr> + </tbody> +</table> +</div> + +<h2 id="相关链接">相关链接</h2> + +<ul> + <li>{{jsxref("Number")}}</li> +</ul> |