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.
The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.
Syntax
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.
HTML content
<div id="example"></div>
JavaScript content
var result = ''; var i = 0; do { i += 1; result += i + ' '; } while (i > 0 && i < 5); // Despite i == 0 this will still loop as it starts off without the test document.getElementById('example').innerHTML = result;
Result
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 Latest Draft (ECMA-262) The definition of 'do-while statement' in that specification. |
Draft |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Update compatibility data on GitHub
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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