do...while
The do...while
statement creates a loop that executes a specified statement until the test condition evaluates to false. The condition is evaluated after executing the statement, resulting in the specified statement executing at least once.
Syntax
JavaScript
Copy Code
do statement while (condition);
statement
- A statement that is executed at least once and is re-executed each time the condition evaluates to true. To execute multiple statements within the loop, use a
block
statement ({ ... }
) to group those statements.
condition
- An expression evaluated after each pass through the loop. If
condition
evaluates to true, thestatement
is re-executed. Whencondition
evaluates to false, control passes to the statement following thedo...while
.
Examples
Using do...while
In the following example, the do...while
loop iterates at least once and reiterates until i
is no longer less than 5.
JavaScript
Copy Code
var i = 0; do { i += 1; console.log(i); } while (i < 5);
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 3rd Edition (ECMA-262) | Standard | Initial definition. Implemented in JavaScript 1.2 |
ECMAScript 5.1 (ECMA-262) The definition of 'do-while statement' in that specification. |
Standard | |
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'do-while statement' in that specification. |
Standard | Trailing ; is now optional. |
ECMAScript 2017 Draft (ECMA-262) The definition of 'do-while statement' in that specification. |
Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | 6 | (Yes) | (Yes) |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
See also
License
© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/javascript/reference/statements/do...while