The Book of JavaScript, 2nd Edition

Setting an Alarm with setTimeout()

The built-in JavaScript function setTimeout() tells JavaScript to run a JavaScript command at some time in the future. The function takes two parameters: a JavaScript command and the time (in milliseconds) to wait before running it. For example, the following line causes an alert box to pop up after a visitor has been on a page for three seconds:

setTimeout("alert('You have been on this page for 3 seconds!');", 3000);

The first setTimeout parameter contains the JavaScript statement to execute. This statement must be enclosed by quotes and, like all JavaScript statements, end with a semicolon. Notice that the string to be displayed by the alert command appears between single quotes rather than double quotes (see ...