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386 lines
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<article id="wikiArticle">
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<div>
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<div></div>
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</div>
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<p><strong><code>for...of</code>语句</strong>在<a href="Guide/iterable">可迭代对象</a>（包括 <a href="Reference/Array" title="REDIRECT Array"><code>Array</code></a>，<a href="Reference/Map" title="此页面仍未被本地化, 期待您的翻译!"><code>Map</code></a>，<a href="Reference/Global_Objects/Set" title="Set 对象允许你存储任何类型的唯一值，无论是原始值或者是对象引用。"><code>Set</code></a>，<a href="Reference/String" title="此页面仍未被本地化, 期待您的翻译!"><code>String</code></a>，<a href="Reference/Global_Objects/TypedArray" title="一个TypedArray 对象描述一个底层的二进制数据缓存区的一个类似数组(array-like)视图。事实上，没有名为 TypedArray的全局对象，也没有一个名为的 TypedArray构造函数。相反，有许多不同的全局对象，下面会列出这些针对特定元素类型的类型化数组的构造函数。在下面的页面中，你会找到一些不管什么类型都公用的属性和方法。"><code>TypedArray</code></a>，<a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions_and_function_scope/arguments">arguments</a> 对象等等）上创建一个迭代循环，调用自定义迭代钩子，并为每个不同属性的值执行语句</p>
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<div><iframe class="interactive interactive-js" frameborder="0" height="250" src="https://interactive-examples.mdn.mozilla.net/pages/js/statement-forof.html" width="100%"></iframe></div>
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<p class="hidden">The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone <a class="external" href="https://github.com/mdn/interactive-examples" rel="noopener">https://github.com/mdn/interactive-examples</a> and send us a pull request.</p>
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<h2 id="语法">语法</h2>
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<pre><code class="language-javascript">for (variable of iterable) {
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//<em>statements</em>
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}
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</code></pre>
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<dl>
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<dt><code>variable</code></dt>
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<dd>在每次迭代中，将不同属性的值分配给变量。</dd>
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<dt><code>iterable</code></dt>
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<dd>被迭代枚举其属性的对象。</dd>
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</dl>
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<h2 id="示例">示例</h2>
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<h3 id="迭代Array">迭代<a href="Reference/Array" title="REDIRECT Array"><code>Array</code></a></h3>
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<pre><code class="language-javascript">let iterable = [10, 20, 30];
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for (let value of iterable) {
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value += 1;
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console.log(value);
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}
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// 11
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// 21
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// 31
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</code></pre>
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<p>如果你不想修改语句块中的变量 , 也可以使用<a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/const"><code>const</code></a>代替<code><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/let">let</a></code>。</p>
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<pre><code class="language-javascript">let iterable = [10, 20, 30];
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for (const value of iterable) {
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console.log(value);
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}
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// 10
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// 20
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// 30</code></pre>
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<h3 id="迭代String">迭代<a href="Reference/String" title="此页面仍未被本地化, 期待您的翻译!"><code>String</code></a></h3>
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<pre><code class="language-javascript">let iterable = "boo";
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for (let value of iterable) {
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console.log(value);
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}
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// "b"
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// "o"
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// "o"</code></pre>
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<h3 id="迭代_TypedArray">迭代 <a href="Reference/Global_Objects/TypedArray" title="一个TypedArray 对象描述一个底层的二进制数据缓存区的一个类似数组(array-like)视图。事实上，没有名为 TypedArray的全局对象，也没有一个名为的 TypedArray构造函数。相反，有许多不同的全局对象，下面会列出这些针对特定元素类型的类型化数组的构造函数。在下面的页面中，你会找到一些不管什么类型都公用的属性和方法。"><code>TypedArray</code></a></h3>
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<pre><code class="language-javascript">let iterable = new Uint8Array([0x00, 0xff]);
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for (let value of iterable) {
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console.log(value);
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}
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// 0
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// 255
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</code></pre>
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<h3 id="迭代Map">迭代<a href="Reference/Map" title="此页面仍未被本地化, 期待您的翻译!"><code>Map</code></a></h3>
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<pre><code class="language-javascript">let iterable = new Map([["a", 1], ["b", 2], ["c", 3]]);
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for (let entry of iterable) {
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console.log(entry);
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}
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// ["a", 1]
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// ["b", 2]
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// ["c", 3]
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for (let [key, value] of iterable) {
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console.log(value);
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}
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// 1
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// 2
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// 3
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</code></pre>
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<h3 id="迭代_Set">迭代 <a href="Reference/Global_Objects/Set" title="Set 对象允许你存储任何类型的唯一值，无论是原始值或者是对象引用。"><code>Set</code></a></h3>
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<pre><code class="language-javascript">let iterable = new Set([1, 1, 2, 2, 3, 3]);
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for (let value of iterable) {
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console.log(value);
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}
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// 1
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// 2
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// 3</code></pre>
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<h3 id="迭代_arguments_对象">迭代 <a class="new" href="Reference/arguments" rel="nofollow" title="此页面仍未被本地化, 期待您的翻译!"><code>arguments</code></a> 对象</h3>
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<pre><code class="language-javascript">(function() {
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for (let argument of arguments) {
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console.log(argument);
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}
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})(1, 2, 3);
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// 1
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// 2
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// 3</code></pre>
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<h3 id="迭代_DOM_集合">迭代 DOM 集合</h3>
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<p>迭代 DOM 元素集合，比如一个<a href="/zh-CN/docs/Web/API/NodeList" title="NodeList 对象是一个节点的集合，是由 Node.childNodes 和 document.querySelectorAll 返回的."><code>NodeList</code></a>对象：下面的例子演示给每一个 article 标签内的 p 标签添加一个 "<code>read</code>" 类。</p>
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<pre><code class="language-js">//注意：这只能在实现了NodeList.prototype[Symbol.iterator]的平台上运行
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let articleParagraphs = document.querySelectorAll("article > p");
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for (let paragraph of articleParagraphs) {
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paragraph.classList.add("read");
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}
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</code></pre>
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<h3 id="关闭迭代器">关闭迭代器</h3>
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<p>对于<code>for...of</code>的循环，可以由<code>break</code>, <code>throw continue </code> 或<code>return</code>终止。在这些情况下，迭代器关闭。</p>
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<pre><code class="language-javascript">function* foo(){
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yield 1;
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yield 2;
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yield 3;
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};
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for (let o of foo()) {
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console.log(o);
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break; // closes iterator, triggers return
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}
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</code></pre>
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<h3 id="迭代生成器">迭代生成器</h3>
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<p><span><span>你还可以</span></span>迭代<span><span>一个</span></span><a href="Reference/Statements/function*">生成器</a>：</p>
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<pre><code class="language-js">function* fibonacci() { // 一个生成器函数
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let [prev, curr] = [0, 1];
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for (;;) { // while (true) {
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[prev, curr] = [curr, prev + curr];
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yield curr;
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}
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}
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for (let n of fibonacci()) {
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console.log(n);
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// 当n大于1000时跳出循环
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if (n >= 1000)
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break;
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}</code></pre>
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<h4 id="不要重用生成器">不要重用生成器</h4>
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<p>生成器不应该重用，即使<code>for...of</code>循环的提前终止，例如通过<a href="Reference/Statements/break" title="break 语句中止当前循环，switch语句或label 语句，并把程序控制流转到紧接着被中止语句后面的语句。"><code>break</code></a>关键字。在退出循环后，生成器关闭，并尝试再次迭代，不会产生任何进一步的结果。</p>
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<pre><code class="language-javascript">var gen = (function *(){
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yield 1;
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yield 2;
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yield 3;
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})();
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for (let o of gen) {
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console.log(o);
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break;//关闭生成器
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}
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//生成器不应该重用，以下没有意义！
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for (let o of gen) {
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console.log(o);
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}
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</code></pre>
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<h3 id="迭代其他可迭代对象">迭代其他可迭代对象</h3>
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<p>你还可以迭代显式实现<a href="Reference/Iteration_protocols#iterable">可迭代</a>协议的对象：</p>
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<pre><code class="language-javascript">var iterable = {
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[Symbol.iterator]() {
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return {
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i: 0,
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next() {
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if (this.i < 3) {
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return { value: this.i++, done: false };
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}
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return { value: undefined, done: true };
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}
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};
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}
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};
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for (var value of iterable) {
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console.log(value);
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}
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// 0
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// 1
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// 2</code></pre>
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<h3 id="for...of与for...in的区别"><code>for...of</code>与<code>for...in</code>的区别</h3>
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<p>无论是<code>for...in</code>还是<code>for...of</code>语句都是迭代一些东西。它们之间的主要区别在于它们的迭代方式。</p>
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<p><a href="Reference/Statements/for...in" title="for...in语句以任意顺序遍历一个对象的可枚举属性。对于每个不同的属性，语句都会被执行。"><code>for...in</code></a> 语句以原始插入顺序迭代对象的<a href="Enumerability_and_ownership_of_properties">可枚举属性</a>。</p>
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<p><code>for...of</code> 语句遍历<a href="Guide/Iterators_and_Generators#Iterables">可迭代对象</a>定义要迭代的数据。</p>
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<p>以下示例显示了与<a href="Reference/Array" title="REDIRECT Array"><code>Array</code></a>一起使用时，<code>for...of</code>循环和<code>for...in</code>循环之间的区别。</p>
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<pre><code class="language-javascript">Object.prototype.objCustom = function() {};
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Array.prototype.arrCustom = function() {};
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let iterable = [3, 5, 7];
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iterable.foo = 'hello';
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for (let i in iterable) {
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console.log(i); // logs 0, 1, 2, "foo", "arrCustom", "objCustom"
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}
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for (let i in iterable) {
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if (iterable.hasOwnProperty(i)) {
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console.log(i); // logs 0, 1, 2, "foo"
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}
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}
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for (let i of iterable) {
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console.log(i); // logs 3, 5, 7
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}</code></pre>
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<pre><code class="language-javascript">Object.prototype.objCustom = function() {};
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Array.prototype.arrCustom = function() {};
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let iterable = [3, 5, 7];
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iterable.foo = 'hello';
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</code></pre>
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<p>每个对象将继承<code>objCustom</code>属性，并且作为<a href="Reference/Array" title="REDIRECT Array"><code>Array</code></a>的每个对象将继承<code>arrCustom</code>属性，因为将这些属性添加到<a href="Reference/Global_Objects/Object/prototype" title="Object.prototype 属性表示 Object 的原型对象。"><code>Object.prototype</code></a>和<a href="Reference/Global_Objects/Array/prototype" title="Array.prototype 属性表示 Array 构造函数的原型，并允许您向所有Array对象添加新的属性和方法。"><code>Array.prototype</code></a>。由于<a href="Inheritance_and_the_prototype_chain">继承和原型链</a>，对象<code>iterable</code>继承属性<code>objCustom</code>和<code>arrCustom</code>。</p>
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<pre><code class="language-javascript">for (let i in iterable) {
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console.log(i); // logs 0, 1, 2, "foo", "arrCustom", "objCustom"
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}
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</code></pre>
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<p>此循环仅以原始插入顺序记录<code>iterable</code> 对象的<a href="Enumerability_and_ownership_of_properties">可枚举属性</a>。它不记录数组<strong>元素</strong><code>3</code>, <code>5</code>, <code>7</code> 或<code>hello</code>，因为这些<strong>不是</strong>枚举属性。但是它记录了数组<strong>索引</strong>以及<code>arrCustom</code>和<code>objCustom</code>。如果你不知道为什么这些属性被迭代，<a href="Reference/Statements/for...in#Array_iteration_and_for...in" title="for...in语句以任意顺序遍历一个对象的可枚举属性。对于每个不同的属性，语句都会被执行。"><code>array iteration and for...in</code></a>中有更多解释。</p>
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<pre><code class="language-javascript">for (let i in iterable) {
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if (iterable.hasOwnProperty(i)) {
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console.log(i); // logs 0, 1, 2, "foo"
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}
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}
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</code></pre>
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<p>这个循环类似于第一个，但是它使用<a href="Reference/Global_Objects/Object/hasOwnProperty" title="hasOwnProperty() 方法会返回一个布尔值，指示对象自身属性中是否具有指定的属性"><code>hasOwnProperty()</code></a> 来检查，如果找到的枚举属性是对象自己的（不是继承的）。如果是，该属性被记录。记录的属性是<code>0</code>, <code>1</code>, <code>2</code>和<code>foo</code>，因为它们是自身的属性（<strong>不是继承的</strong>）。属性<code>arrCustom</code>和<code>objCustom</code>不会被记录，因为它们<strong>是继承的</strong>。</p>
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<pre><code class="language-javascript">for (let i of iterable) {
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console.log(i); // logs 3, 5, 7
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}
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</code></pre>
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<p>该循环迭代并记录<code>iterable</code>作为<a href="Guide/Iterators_and_Generators#Iterables">可迭代对象</a>定义的迭代值，这些是数组元素 <code>3</code>, <code>5</code>, <code>7</code>，而不是任何对象的<strong>属性</strong>。</p>
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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-for-in-and-for-of-statements" hreflang="en" lang="en" rel="noopener">ECMAScript 2015 (6th Edition, ECMA-262)<br/><small lang="zh-CN">for...of statement</small></a></td>
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<td><span class="spec-Standard">Standard</span></td>
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<td>Initial definition.</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-for-in-and-for-of-statements" hreflang="en" lang="en" rel="noopener">ECMAScript Latest Draft (ECMA-262)<br/><small lang="zh-CN">for...of statement</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">浏览器兼容</h2>
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<div class="hidden">The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out <a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</div>
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<p></p><div class="bc-data"><a class="bc-github-link external" href="https://github.com/mdn/browser-compat-data" rel="noopener">Update compatibility data on GitHub</a><table class="bc-table bc-table-js"><thead><tr class="bc-platforms"><td></td><th class="bc-platform-desktop" colspan="6"><span>Desktop</span></th><th class="bc-platform-mobile" colspan="7"><span>Mobile</span></th><th class="bc-platform-server" colspan="1"><span>Server</span></th></tr><tr class="bc-browsers"><td></td><th class="bc-browser-chrome"><span class="bc-head-txt-label bc-head-icon-chrome">Chrome</span></th><th class="bc-browser-edge"><span class="bc-head-txt-label bc-head-icon-edge">Edge</span></th><th class="bc-browser-firefox"><span class="bc-head-txt-label bc-head-icon-firefox">Firefox</span></th><th class="bc-browser-ie"><span class="bc-head-txt-label bc-head-icon-ie">Internet Explorer</span></th><th class="bc-browser-opera"><span class="bc-head-txt-label bc-head-icon-opera">Opera</span></th><th class="bc-browser-safari"><span class="bc-head-txt-label bc-head-icon-safari">Safari</span></th><th class="bc-browser-webview_android"><span class="bc-head-txt-label bc-head-icon-webview_android">Android webview</span></th><th class="bc-browser-chrome_android"><span class="bc-head-txt-label bc-head-icon-chrome_android">Chrome for Android</span></th><th class="bc-browser-edge_mobile"><span class="bc-head-txt-label bc-head-icon-edge_mobile">Edge Mobile</span></th><th class="bc-browser-firefox_android"><span class="bc-head-txt-label bc-head-icon-firefox_android">Firefox for Android</span></th><th class="bc-browser-opera_android"><span class="bc-head-txt-label bc-head-icon-opera_android">Opera for Android</span></th><th class="bc-browser-safari_ios"><span class="bc-head-txt-label bc-head-icon-safari_ios">Safari on iOS</span></th><th class="bc-browser-samsunginternet_android"><span class="bc-head-txt-label bc-head-icon-samsunginternet_android">Samsung Internet</span></th><th class="bc-browser-nodejs"><span class="bc-head-txt-label bc-head-icon-nodejs">Node.js</span></th></tr></thead><tbody><tr><th scope="row"><code>for...of</code></th><td class="bc-supports-yes bc-browser-chrome"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-yes only-icon" title="Full support">
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||
<span>Full support</span>
|
||
</abbr>
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||
38</td><td class="bc-supports-yes bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr class="bc-level-yes only-icon" title="Full support">
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||
<span>Full support</span>
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||
</abbr>
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||
12</td><td class="bc-supports-yes bc-browser-firefox bc-has-history"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
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||
<span>Full support</span>
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||
</abbr>
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||
13<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div><section class="bc-history" id="sect1"><dl><dt class="bc-supports-yes bc-supports"><abbr class="bc-level-yes only-icon" title="Full support">
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||
<span>Full support</span>
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||
</abbr>
|
||
13<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Prior to Firefox 51, using the <code>for...of</code> loop construct with the <code>const</code> keyword threw a <code>SyntaxError</code> ("missing = in const declaration").</dd></dl></section></td><td class="bc-supports-no bc-browser-ie"><span class="bc-browser-name">IE</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-yes bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
25</td><td class="bc-supports-yes bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
8</td><td class="bc-supports-yes bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
38</td><td class="bc-supports-yes bc-browser-chrome_android"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
Yes</td><td class="bc-supports-yes bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
12</td><td class="bc-supports-yes bc-browser-firefox_android bc-has-history"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
14<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div><section class="bc-history" id="sect2"><dl><dt class="bc-supports-yes bc-supports"><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
14<div class="bc-icons"><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> </div></dt><dd><abbr class="only-icon" title="See implementation notes"><span>Notes</span><i class="ic-footnote"></i></abbr> Prior to Firefox 51, using the <code>for...of</code> loop construct with the <code>const</code> keyword threw a <code>SyntaxError</code> ("missing = in const declaration").</dd></dl></section></td><td class="bc-supports-yes bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
25</td><td class="bc-supports-yes bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
8</td><td class="bc-supports-yes bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
Yes</td><td class="bc-supports-yes bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
Yes</td></tr><tr><th scope="row">async iterators</th><td class="bc-supports-yes bc-browser-chrome"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
63</td><td class="bc-supports-unknown bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr title="Compatibility unknown; please update this.">
|
||
?
|
||
</abbr></td><td class="bc-supports-yes bc-browser-firefox"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
57</td><td class="bc-supports-no bc-browser-ie"><span class="bc-browser-name">IE</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-yes bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
50</td><td class="bc-supports-unknown bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr title="Compatibility unknown; please update this.">
|
||
?
|
||
</abbr></td><td class="bc-supports-yes bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
63</td><td class="bc-supports-yes bc-browser-chrome_android"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
63</td><td class="bc-supports-unknown bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr title="Compatibility unknown; please update this.">
|
||
?
|
||
</abbr></td><td class="bc-supports-yes bc-browser-firefox_android"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
57</td><td class="bc-supports-yes bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
50</td><td class="bc-supports-unknown bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr title="Compatibility unknown; please update this.">
|
||
?
|
||
</abbr></td><td class="bc-supports-unknown bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr title="Compatibility unknown; please update this.">
|
||
?
|
||
</abbr></td><td class="bc-supports-unknown bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr title="Compatibility unknown; please update this.">
|
||
?
|
||
</abbr></td></tr><tr><th scope="row">Closing iterators</th><td class="bc-supports-yes bc-browser-chrome"><span class="bc-browser-name">Chrome</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
51</td><td class="bc-supports-yes bc-browser-edge"><span class="bc-browser-name">Edge</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
Yes</td><td class="bc-supports-yes bc-browser-firefox"><span class="bc-browser-name">Firefox</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
53</td><td class="bc-supports-no bc-browser-ie"><span class="bc-browser-name">IE</span><abbr class="bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
</abbr>
|
||
No</td><td class="bc-supports-yes bc-browser-opera"><span class="bc-browser-name">Opera</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
Yes</td><td class="bc-supports-yes bc-browser-safari"><span class="bc-browser-name">Safari</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
Yes</td><td class="bc-supports-yes bc-browser-webview_android"><span class="bc-browser-name">WebView Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
Yes</td><td class="bc-supports-yes bc-browser-chrome_android"><span class="bc-browser-name">Chrome Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
Yes</td><td class="bc-supports-yes bc-browser-edge_mobile"><span class="bc-browser-name">Edge Mobile</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
Yes</td><td class="bc-supports-yes bc-browser-firefox_android"><span class="bc-browser-name">Firefox Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
53</td><td class="bc-supports-yes bc-browser-opera_android"><span class="bc-browser-name">Opera Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
Yes</td><td class="bc-supports-yes bc-browser-safari_ios"><span class="bc-browser-name">Safari iOS</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
Yes</td><td class="bc-supports-yes bc-browser-samsunginternet_android"><span class="bc-browser-name">Samsung Internet Android</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
Yes</td><td class="bc-supports-yes bc-browser-nodejs"><span class="bc-browser-name">nodejs</span><abbr class="bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
</abbr>
|
||
Yes</td></tr></tbody></table><section class="bc-legend" id="sect3"><h3 class="offscreen" id="Legend">Legend</h3><dl><dt><span class="bc-supports-yes bc-supports">
|
||
<abbr class="bc-level bc-level-yes only-icon" title="Full support">
|
||
<span>Full support</span>
|
||
|
||
</abbr></span></dt><dd>Full support</dd><dt><span class="bc-supports-no bc-supports">
|
||
<abbr class="bc-level bc-level-no only-icon" title="No support">
|
||
<span>No support</span>
|
||
|
||
</abbr></span></dt><dd>No support</dd><dt><span class="bc-supports-unknown bc-supports">
|
||
<abbr class="bc-level bc-level-unknown only-icon" title="Compatibility unknown">
|
||
<span>Compatibility unknown</span>
|
||
|
||
</abbr></span></dt><dd>Compatibility unknown</dd><dt><abbr class="only-icon" title="See implementation notes."><span>See implementation notes.</span><i class="ic-footnote"></i></abbr></dt><dd>See implementation notes.</dd></dl></section></div><p></p>
|
||
<h2 id="相关链接">相关链接</h2>
|
||
<ul>
|
||
<li><a href="Reference/Global_Objects/Array/forEach" title="forEach() 方法对数组的每个元素执行一次提供的函数。"><code>Array.prototype.forEach()</code></a></li>
|
||
<li><a href="Reference/Global_Objects/Map/forEach" title="forEach() 方法将会以插入顺序对 Map 对象中的每一个键值对执行一次参数中提供的回调函数。"><code>Map.prototype.forEach()</code></a></li>
|
||
</ul>
|
||
</article> |