setTimeout
Evaluates an expression or calls a function once after a specified number of milliseconds elapses.Method of
window
Implemented in
JavaScript 1.0: evaluating an expression
JavaScript 1.2: calling a function
Syntax
setTimeout(expression, msec)setTimeout(function, msec[, arg1[, ..., argN]])
Parameters
expression
A string containing a JavaScript expression. The expression must be quoted; otherwise, setTimeout calls it immediately. For example, setTimeout("calcnum(3, 2)", 25).
msec
A numeric value or numeric string, in millisecond units.
function
Any function.
arg1, ..., argN
The arguments, if any, passed to function.
Description
The setTimeout method evaluates an expression or calls a function after a specified amount of time. It does not act repeatedly. For example, if a setTimeout method specifies five seconds, the expression is evaluated or the function is called after five seconds, not every five seconds. For repetitive timeouts, use the setInterval method.
setTimeout does not stall the script. The script continues immediately (not waiting for the timeout to expire). The call simply schedules a future event.
Examples
Example 1. The following example displays an alert message five seconds (5,000 milliseconds) after the user clicks a button. If the user clicks the second button before the alert message is displayed, the timeout is canceled and the alert does not display.
<SCRIPT LANGUAGE="JavaScript">function displayAlert() { alert("5 seconds have elapsed since the button was clicked.")}</SCRIPT><BODY><FORM>Click the button on the left for a reminder in 5 seconds; click the button on the right to cancel the reminder before it is displayed.<P><INPUT TYPE="button" VALUE="5-second reminder" NAME="remind_button" onClick="timerID=setTimeout('displayAlert()',5000)"><INPUT TYPE="button" VALUE="Clear the 5-second reminder" NAME="remind_disable_button" onClick="clearTimeout(timerID)"></FORM></BODY>