The Book of JavaScript, 2nd Edition

confirm() [FF, IE 3]

Creates a dialog box with two buttons, OK and Cancel, and text specified by the function's parameter. Clicking OK results in the function returning a value of true, and clicking Cancel results in a false value.

Example:

if (confirm("Are you feeling happy?"))
{
    alert("Clap your hands!");
} else {
    alert("Don't worry!");
}

This example calls up a dialog box with the text Are you feeling happy? along with an OK button and a Cancel button. Clicking the OK button causes the function to return true, executing the first part of the if-then-else statement with an alert box showing the words Clap your hands! Clicking Cancel causes the function to return false, triggering the else clause of the if-then-else statement and calling an alert ...