I needed to find the current day of the year in javascript. Here's a snippet which helps you do that.

dayOfYear.js

// Taken from http://www.devcurry.com/2011/08/javascript-find-day-of-year.html
var timeStamp = new Date().setFullYear(new Date().getFullYear(), 0, 1);
var yearFirstDay = Math.floor(timeStamp / 86400000);
var today = Math.ceil((new Date().getTime()) / 86400000);
var dayOfYear = today - yearFirstDay;

// If you want hours, you can just multiply by 24.
// I subtracted by 24 because I wanted the beginning of the day, not the end!
var hoursOfYear = dayOfYear * 24 - 24

// If you want the CURRENT hour, you need what the hour is now and simply add it to hoursOfYear
var currentHourInYear = dayOfYear + [what-ever-the-hour-is-now];