Question: how to calculate time difference in html?
Answer: Sample Solution:-
HTML Code: <! ... 
JavaScript Code: function diff_minutes(dt2, dt1) { var diff =(dt2.getTime() - dt1.getTime()) / 1000; diff /= 60; return Math.abs(Math.round(diff)); } dt1 = new Date(2014,10,2); dt2 = new Date(2014,10,3); console.log(diff_minutes(dt1, dt2)); ... 
Flowchart:
Live Demo: