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while Statement

while Statement (JavaScript)

Executes a statement or series of statements until a specified condition is false.

while (expression) {


Required. A Boolean expression that is checked before each iteration of the loop. If expression is true, the loop is executed. If expression is false, the loop is terminated.


Optional. One or more statements to be executed if expression is true.

The while statement checks expression before a loop is first executed. If expression is false at this time, the loop is never executed.

The following example illustrates the use of the while statement.

var i = 0;
var j = 10;
while (i < 100) {
    if (i == j)

// Output: 10

Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards, Internet Explorer 10 standards, Internet Explorer 11 standards. Also supported in Store apps (Windows 8 and Windows Phone 8.1). See Version Information.

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