I am trying to add two dates:
date start Fri Apr 26 2013 16:08:03 GMT+0100 (Paris, Madrid)
+
date periode Fri Apr 26 2013 00:10:00 GMT+0100 (Paris, Madrid
If you want to add a time period to a date, you basically have to convert both of them into milliseconds.
var date = new Date();
var dateMillis = date.getTime();
//JavaScript doesn't have a "time period" object, so I'm assuming you get it as a string
var timePeriod = "00:15:00"; //I assume this is 15 minutes, so the format is HH:MM:SS
var parts = timePeriod.split(/:/);
var timePeriodMillis = (parseInt(parts[0], 10) * 60 * 60 * 1000) +
(parseInt(parts[1], 10) * 60 * 1000) +
(parseInt(parts[2], 10) * 1000);
var newDate = new Date();
newDate.setTime(dateMillis + timePeriodMillis);
console.log(date); //eg: Fri Apr 26 2013 08:52:50 GMT-0700 (MST)
console.log(newDate); //eg: Fri Apr 26 2013 09:07:50 GMT-0700 (MST)