function ClearMe (Ctarget, defaultval) {
 if (Ctarget.value == defaultval) Ctarget.value = '';
}
function CheckMe (Ctarget, defaultval) {
 if (Ctarget.value == '') Ctarget.value = defaultval;
}

function updateTimer(timerID) {
 timer_remaining = 12*60-(timer_current-timer_start-timer_offset);
 timer_remaining_minutes = Math.floor(timer_remaining/60);
 timer_remaining_seconds = timer_remaining%60;
 document.getElementById(timerID).innerHTML = timer_remaining_minutes + ":" + timer_remaining_seconds;
 timer_offset++;
}