Jquery time difference in hours from two fields

Question

I have two fields in my form where users select an input time (start_time, end_time) I would like to, on the change of these fields, recalcuate the value for another field.<

Answer 1

try

var diff = ( new Date("1970-1-1 " + end_time) - new Date("1970-1-1 " + start_time) ) / 1000 / 60 / 60;  

have a fiddle