onMouseOver Delay?

I'm trying to create an action that delays an action for a few seconds before the action occurs.

An example would be a button has two ways to activate a followon action.

On way would be on click.
The second would be onMouseOver but with a twist.

If the user holds the cursor on teh button for about 3 seconds - the action triggers.

If they just roll over the button with a time of less than 3 seconds - nothing happens.

Any ideas on how to program the delay?

A simple if statement?