while

Availability

Flash Player 4.

Usage

while(condition) {
  statement(s);
}

Parameters

condition The expression that is reevaluated each time the while action is executed.

statement(s) The instructions to execute while the condition evaluates to true.

Returns

Nothing.

Description

Statement; tests an expression and runs a statement or series of statements repeatedly in a loop as long as the expression is true.

Before the statement block is run, the condition is tested; if the test returns true, the statement block is run. If the condition is false, the statement block is skipped and the first statement after the while action's statement block is executed.

Looping is commonly used to perform an action while a counter variable is less than a specified value. At the end of each loop, the counter is incremented until the specified value is reached. At that point, the condition is no longer true, and the loop ends.

The while statement performs the following series of steps. Each repetition of steps 1-4 is called an iteration of the loop. The condition is retested at the beginning of each iteration, as in the following steps:

  1. The expression condition is evaluated.
  2. If condition evaluates to true or a value that converts to the Boolean value true, such as a nonzero number, go to step 3.

    Otherwise, the while statement is completed and execution resumes at the next statement after the while loop.

  3. Run the statement block statement(s).
  4. Go to step 1.

See also

do while, continue, for, for..in