Question

For Example:

StartTime = '00:10';
EndTIme = '01:20';

These variables are string

Question: How can I Subtract them and returning the span time in minutes?

Hope you can help

Answer 1

Make a function to parse a string like that into minutes:

function parseTime(s) {
   var c = s.split(':');
   return parseInt(c[0]) * 60 + parseInt(c[1]);
}

Now you can parse the strings and just subtract:

var minutes = parseTime(EndTIme) - parseTime(StartTime);