do...while

do...while 语句创建一个执行指定语句的循环,直到condition值为 false。在执行statement 后检测condition,所以指定的statement至少执行一次。

语法

do
   statement
while (condition);
statement
执行至少一次的语句,并在每次 condition 值为真时重新执行。想执行多行语句,可使用 block语句 { ... } 包裹这些语句。
condition
循环中每次都会计算的表达式。如果 condition 值为真, statement 会再次执行。当 condition 值为假,则跳到 do...while之后的语句。

示例

使用 do...while

下面的例子中,do...while 循环至少迭代一次,并且继续迭代直到 i不再小于 5 时结束。

HTML 内容

<div id="example"></div>

JavaScript 内容

var result = '';
var i = 0;
do {
   i += 1;
   result += i + ' ';
} while (i < 5);
document.getElementById('example').innerHTML = result;

结果

规范

Specification Status Comment
ECMAScript 3rd Edition (ECMA-262) Standard Initial definition. Implemented in JavaScript 1.2
ECMAScript 5.1 (ECMA-262)
do-while statement
Standard  
ECMAScript 2015 (6th Edition, ECMA-262)
do-while statement
Standard Trailing ; is now optional.
ECMAScript Latest Draft (ECMA-262)
do-while statement
Draft  

浏览器兼容

Update compatibility data on GitHub
Desktop Mobile Server
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet Node.js
do...while Chrome Full support 1 Edge Full support 12 Firefox Full support 1 IE Full support 4 Opera Full support Yes Safari Full support Yes WebView Android Full support 1 Chrome Android Full support 18 Firefox Android Full support 4 Opera Android Full support Yes Safari iOS Full support Yes Samsung Internet Android Full support 1.0 nodejs Full support Yes

Legend

Full support  
Full support

相关链接