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
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, the statement is re-executed. When condition evaluates to false, control passes to the statement following the do...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
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

JavaScript Statement