How to get value from MKB Time Selector

I had used a MKB Time Selector in my asp page, there is a javascript to calculate the duration between "From Date" and "To Date".

But i cannot get the value from Time selector, do you have any idea ?

my code:

function cal_dur() {

var ctl_from_time = document.forms[0].ctl00_CPH1_TimeSelector_from_time;

var ctl_to_time = document.forms[0].ctl00_CPH1_TimeSelector_to_time;

.....

}

Thanks

Joe