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);

Description

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.

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

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