JavaScript do...while Loop
Example
Execute a code block once, an then continue if condition (i < 5) is true:
let text = "";
let i = 0;
do {
text += i + "<br>";
i++;
}
while (i < 5);
Try it Yourself »
Definition and Usage
The do...while statements combo defines a code block to be executed once,
and repeated as long as a condition is true.
The do...while is used when you want to run a code block at least one time.
Note
If you use a variable in the condition, you must initialize it before the loop, and increment it within the loop. Otherwise the loop will never end. This will crash your browser.
If the condition is always true, the loop will never end. This will also crash your browser.
See Also:
Syntax
do {
code block to be executed
}
while (condition);
Parameters
| Parameter | Description |
| condition | Required. The condition for running the code block. If true, the loop will start over again, otherwise it ends. |
JavaScript Loop Statements
| Statement | Description | |
| break | Breaks out of a loop | |
| continue | Skips a value in a loop | |
| while | Loops a code block while a condition is true | |
| do...while | Loops a code block once, and then while a condition is true | |
| for | Loops a code block while a condition is true | |
| for...of | Loops the values of any iterable | |
| for...in | Loops the properties of an object |
Browser Support
do..while is an ECMAScript1 (ES1) feature.
ES1 (JavaScript 1997) is fully supported in all browsers:
| Chrome | Edge | Firefox | Safari | Opera | IE |
| Yes | Yes | Yes | Yes | Yes | Yes |
