confusion over setTimeout and clearTimeout

Question

I have a button that changes the background of a div when its rolled over. the background needs to change on a timer so i have used setTimout to execute methods that change

Answer 1

Assign a variable to your setTimeout, which you then pass to clearTimeout to clear it, i.e.

var play_timeout = setTimeout("playV()", 2700);
clearTimeout(play_timeout);

(Note I added quotes around your first setTimeout argument)