setInterval and setTimeout example.

// To execute a function every two seconds, you do this:

var interval = setInterval(function() { alert("Hello"); }, 2000);

// Then to clear the interval (I.E. Stop it) you just do this:

clearInterval(interval);

// And to execute a function once after a certain amount of time, you simply use this instead:

var timeout = setTimeout(function() { alert("Hello"); }, 2000);

// And to clear the timeout (I.E. Stop it before executing the function) you do this:

clearTimeout(timeout);