jquery - parse date string in JavaScript to get timezone offset -

i have date string fri, 15 nov 2013 09:00:00 -0600 in javascript(sent server php). need parse , timezone offset '-0600'. there easy way timezone offset string?

thanks

var str = "fri, 15 nov 2013 09:00:00 -0600" var output = str.split(' ').pop(); 

demo: http://jsfiddle.net/d7c28/