var timeSpent = 0; function timer() { setTimeout('timer()', 1000); if(!document.forms['form1']) return; //Form doesn't exist if(!document.forms['form1'].elements['pause']) return; //Form improperly loaded if(document.forms['form1'].elements['pause'].checked) return; //Paused timeSpent++; var seconds = timeSpent%60; if(seconds < 10) seconds = "0" + seconds.toString(); var minutes = (timeSpent-seconds)/60; document.forms['form1'].elements['timespent'].value = minutes + ":" + seconds; } window.onload = timer;