var time_start = new Date();
var clock_start = time_start.getTime();

function get_time_spent ()
{ 
var time_now = new Date();
return((time_now.getTime() - clock_start)/1000); 
}

function show_secs () // show the time user spent on the side
{ 
var i_total_secs = Math.round(get_time_spent()); 
var i_secs_spent = i_total_secs % 60;
var i_mins_spent = Math.round((i_total_secs-30)/60); 
var s_secs_spent = "" + ((i_secs_spent>9) ? i_secs_spent : "0" + i_secs_spent);
var s_mins_spent = "" + ((i_mins_spent>9) ? i_mins_spent : "0" + i_mins_spent);

document.timerform.time_spent.value = s_mins_spent + ":" + s_secs_spent;
window.setTimeout('show_secs()',1000); 
}