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author | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:43:23 -0500 |
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committer | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:43:23 -0500 |
commit | 218934fa2ed1c702a6d3923d2aa2cc6b43c48684 (patch) | |
tree | a9ef8ac1e1b8fe4207b6d64d3841bfb8990b6fd0 /files/zh-tw/web/javascript/reference/global_objects/number/isfinite | |
parent | 074785cea106179cb3305637055ab0a009ca74f2 (diff) | |
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diff --git a/files/zh-tw/web/javascript/reference/global_objects/number/isfinite/index.html b/files/zh-tw/web/javascript/reference/global_objects/number/isfinite/index.html new file mode 100644 index 0000000000..a15d29c7c0 --- /dev/null +++ b/files/zh-tw/web/javascript/reference/global_objects/number/isfinite/index.html @@ -0,0 +1,93 @@ +--- +title: Number.isFinite() +slug: Web/JavaScript/Reference/Global_Objects/Number/isFinite +tags: + - JavaScript + - Method + - Number + - Reference +translation_of: Web/JavaScript/Reference/Global_Objects/Number/isFinite +--- +<div>{{JSRef}}</div> + +<p><strong><code>Number.isFinite()</code></strong> 方法會判斷傳入的值是否為有限數(finite number)。</p> + +<div>{{EmbedInteractiveExample("pages/js/number-isfinite.html")}}</div> + + + +<h2 id="語法">語法</h2> + +<pre class="syntaxbox">Number.isFinite(v<var>alue</var>)</pre> + +<h3 id="參數">參數</h3> + +<dl> + <dt><code>value</code></dt> + <dd>The value to be tested for finiteness.</dd> +</dl> + +<h3 id="回傳值">回傳值</h3> + +<p>A {{jsxref("Boolean")}} indicating whether or not the given value is a finite number.</p> + +<h2 id="說明">說明</h2> + +<p>In comparison to the global {{jsxref("isFinite", "isFinite()")}} function, this method doesn't forcibly convert the parameter to a number. This means only values of the type number, that are also finite, return <code>true</code>.</p> + +<h2 id="範例">範例</h2> + +<pre class="brush: js">Number.isFinite(Infinity); // false +Number.isFinite(NaN); // false +Number.isFinite(-Infinity); // false + +Number.isFinite(0); // true +Number.isFinite(2e64); // true + +Number.isFinite('0'); // false, would've been true with + // global isFinite('0') +Number.isFinite(null); // false, would've been true with + // global isFinite(null) +</pre> + +<h2 id="Polyfill">Polyfill</h2> + +<pre class="brush: js">Number.isFinite = Number.isFinite || function(value) { + return typeof value === 'number' && isFinite(value); +} +</pre> + +<h2 id="規範">規範</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.isfinite', 'Number.isInteger')}}</td> + <td>{{Spec2('ES6')}}</td> + <td>Initial definition.</td> + </tr> + <tr> + <td>{{SpecName('ESDraft', '#sec-number.isfinite', 'Number.isInteger')}}</td> + <td>{{Spec2('ESDraft')}}</td> + <td> </td> + </tr> + </tbody> +</table> + +<h2 id="瀏覽器相容性">瀏覽器相容性</h2> + +<p class="hidden">The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out <a href="https://github.com/mdn/browser-compat-data">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</p> + +<p>{{Compat("javascript.builtins.Number.isFinite")}}</p> + +<h2 id="參見">參見</h2> + +<ul> + <li>The {{jsxref("Number")}} object it belongs to.</li> + <li>The global function {{jsxref("isFinite")}}.</li> +</ul> |