How to get a year first date and last date in javascript -

need first date , last date time of year passing year number. it's below.

var year = 2016 //any year var first_date = ? //from year var last_date = ? //from year 

var year = 2016 //any year  var first_date = new date(year, 0, 1);  var last_date = new date(year, 11, 31);    document.write(first_date);  document.write("<br/>");  document.write(last_date);