Time difference in JQuery

Question

I need to subtract two 24-hour time values from 0 to 23 using JQuery.

e.g. , 01:00 - 03:00 should return 22:00 hours

but my function's not working

function TimeDiff()
{
    var start=$('#fTime').val();    
    var end = '03:00';
    var diff=(start-end+24)%24;
    $('#bReg').val(diff);   
}

Do I need to do some sort of conversion to Time object or ...?

Any ideas? ^..^

Answer 1

check this demo please, i wrote a demo for you, you can use it;

http://jsfiddle.net/BSeN6/2/

Answer 2

var diff =
    new Date( '01/01/2009 ' + $('#fTime').val()) -
    new Date( '01/01/2009 ' + "03:00 PM" );

var hours=(diff / 1000)+"";//just to make it a string

use hours+":00" for outputs like "22:00" hrs Also, find the time format should have a AM/PM