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+---
+title: Array.isArray()
+slug: Web/JavaScript/Reference/Global_Objects/Array/isArray
+tags:
+ - ECMAScript5
+ - JavaScript
+ - 'brush: js'
+ - class=
+ - polyfill
+ - 数组
+ - 方法
+translation_of: Web/JavaScript/Reference/Global_Objects/Array/isArray
+---
+<div>{{JSRef}}</div>
+
+<p><strong>Array.isArray() </strong>用于确定传递的值是否是一个 {{jsxref("Array")}}。</p>
+
+<pre class="brush: js">Array.isArray([1, 2, 3]);
+// true
+Array.isArray({foo: 123});
+// false
+Array.isArray("foobar");
+// false
+Array.isArray(undefined);
+// false
+</pre>
+
+<h2 id="语法">语法</h2>
+
+<pre>Array.isArray(<var>obj</var>)</pre>
+
+<h3 id="参数">参数</h3>
+
+<dl>
+ <dt><code>obj</code></dt>
+ <dd>需要检测的值。</dd>
+</dl>
+
+<h3 id="返回值">返回值</h3>
+
+<p>如果值是 {{jsxref("Array")}},则为true; 否则为false。</p>
+
+<h2 id="描述">描述</h2>
+
+<p>如果对象是 {{jsxref("Array")}} ,则返回true,否则为false。</p>
+
+<p>有关更多详细信息,请参阅文章<a href="http://web.mit.edu/jwalden/www/isArray.html">严格判定JavaScript对象是否为数组</a>。</p>
+
+<p>See the article <a href="http://web.mit.edu/jwalden/www/isArray.html">“Determining with absolute accuracy whether or not a JavaScript object is an array”</a> for more details. Given a {{jsxref("TypedArray")}} instance, <code>false</code> is always returned.</p>
+
+<h2 id="示例">示例</h2>
+
+<pre class="brush: js">// 下面的函数调用都返回 true
+Array.isArray([]);
+Array.isArray([1]);
+Array.isArray(new Array());
+Array.isArray(new Array('a', 'b', 'c', 'd'))
+// 鲜为人知的事实:其实 Array.prototype 也是一个数组。
+Array.isArray(Array.prototype);
+
+// 下面的函数调用都返回 false
+Array.isArray();
+Array.isArray({});
+Array.isArray(null);
+Array.isArray(undefined);
+Array.isArray(17);
+Array.isArray('Array');
+Array.isArray(true);
+Array.isArray(false);
+Array.isArray(new Uint8Array(32))
+Array.isArray({ __proto__: Array.prototype });
+</pre>
+
+<h3 id="instanceof_和_isArray"><code>instanceof</code> 和 <code>isArray</code></h3>
+
+<p>当检测Array实例时, <code>Array.isArray</code> 优于 <code>instanceof</code>,因为Array.isArray能检测<code>iframes</code>.</p>
+
+<pre><code>var iframe = document.createElement('iframe');
+document.body.appendChild(iframe);
+xArray = window.frames[window.frames.length-1].Array;
+var arr = new xArray(1,2,3); // [1,2,3]
+
+// Correctly checking for Array
+Array.isArray(arr); // true
+// Considered harmful, because doesn't work though iframes
+arr instanceof Array; // false</code></pre>
+
+<h2 id="Polyfill">Polyfill</h2>
+
+<p>假如不存在 Array.isArray(),则在其他代码之前运行下面的代码将创建该方法。</p>
+
+<pre class="brush: js">if (!Array.isArray) {
+ Array.isArray = function(arg) {
+ return Object.prototype.toString.call(arg) === '[object Array]';
+ };
+}
+</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('ES5.1', '#sec-15.4.3.2', 'Array.isArray')}}</td>
+ <td>{{Spec2('ES5.1')}}</td>
+ <td>Initial definition. Implemented in JavaScript 1.8.5.</td>
+ </tr>
+ <tr>
+ <td>{{SpecName('ES6', '#sec-array.isarray', 'Array.isArray')}}</td>
+ <td>{{Spec2('ES6')}}</td>
+ <td></td>
+ </tr>
+ <tr>
+ <td>{{SpecName('ESDraft', '#sec-array.isarray', 'Array.isArray')}}</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>
+<div>
+
+
+<p>{{Compat("javascript.builtins.Array.isArray")}}</p>
+</div>
+</div>
+
+<h2 id="相关链接">相关链接</h2>
+
+<ul>
+ <li>{{jsxref("Array")}}</li>
+</ul>