Julian day conversion

NOAA keeps a handy Javascript application at the webpage below for converting a normal calendar date into Julian days. The catch is that it does this conversion using January 1 of any year as Julian day 1, rather than calculating Julian day from noon on January 1, 4713 BC. So in reality, this converts your date to the "day of year" rather than true Julian date. Most sites on the web give you a Julian date starting from the ancient date. For certain calculations, it is just simpler to express your date within a year as the day-of-year (i.e. 1 - 365, 366 on a leap year). This NOAA calculator does this for you.

http://autochart.pmel.noaa.gov:1776/autochart/date2jday.html