JavaScript 的 For


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for of 循环

JavaScript for of 语句循环 通过可迭代对象的值。

它允许您循环遍历可迭代的数据结构 例如数组、字符串、映射、节点列表等:

句法

for (variable of iterable) {
  // code block to be executed
}

变量 - 对于每次迭代,下一个属性的值为 分配给变量。 变量可以用以下方式声明 constletvar

iterable - 具有可迭代属性的对象。


浏览器支持

For/of 于 2015 年添加到 JavaScript (ES6)

Safari 7 是第一个支持以下功能的浏览器:

Chrome 38 Edge 12 Firefox 51 Safari 7 Opera 25
Oct 2014 Jul 2015 Oct 2016 Oct 2013 Oct 2014

Internet Explorer 不支持For/of


循环数组

例子

const cars = ["BMW", "Volvo", "Mini"];

let text = "";
for (let x of cars) {
  text += x;
}

自己尝试一下→

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript For Of Loop</h2>
<p>The for of statement loops through the values of any iterable object:</p>

<p id="demo"></p>

<script>
const cars = ["BMW", "Volvo", "Mini"];

let text = "";
for (let x of cars) {
  text += x + "<br>";
}

document.getElementById("demo").innerHTML = text;
</script>

</body>
</html>

循环字符串

例子

let language = "JavaScript";

let text = "";
for (let x of language) {
  text += x;
}

自己尝试一下 →

<!DOCTYPE html>
<html>
<body>

<h2>JavaScript For Of Loop</h2>

<p>The for of statement loops through the values of an iterable object.</p>

<p id="demo"></p>

<script>
let language = "JavaScript";

let text = "";
for (let x of language) {
  text += x + "<br>";
}

document.getElementById("demo").innerHTML = text;
</script>

</body>
</html>

While 循环

while 循环和 do/while 循环将在下一章中解释。