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.


while (condition);
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.
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.


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.

var i = 0;
do {
   i += 1;
} while (i < 5);


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.
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.

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

Document Tags and Contributors

 Last updated by: fscholz,