How do you convert a JavaScript date to UTC?

Question

Suppose a user of your website enters a date range.

2009-1-1 to 2009-1-3

You need to send this date to a server for some processing, but th

Answer 1

var userdate = new Date("2009-1-1T8:00:00Z");
var timezone = userdate.getTimezoneOffset();
var serverdate = new Date(userdate.setMinutes(userdate.getMinutes()+parseInt(timezone)));

This will give you the proper UTC Date and Time.
It's because the getTimezoneOffset() will give you the timezone difference in minutes. I recommend you that not to use toISOString() because the output will be in the string Hence in future you will not able to manipulate the date