Given the output you’re stuck with, I can’t think of any better way to catch a DateTime of 0 on the javascript side.
Date.parse should work for your parsing needs, but it returns number of milliseconds, so you need to wrap a Date constructor around it:
var date = new Date(Date.parse(myCSharpString));
For the return date, you simply want
date.getFullYear() + "https://stackoverflow.com/" + (date.getMonth() + 1) + "https://stackoverflow.com/" + (date.getDate() + 1);
(date.getMonth and date.getDate are 0-indexed instead of 1-indexed.)
Fiddle: http://jsfiddle.net/GyC3t/
EDIT
Thanks to JoeB’s catch, let me do a correction. The date.getMonth() function is 0-indexed, but the date.getDate() function is 1-indexed. The fiddle was “working” with the +1 because date.getMonth works in local time, which is before UTC. I didn’t properly check the docs, and just added 1, and it worked with the fiddle.
A more proper way to do this is:
For the return date, you simply want
date.getFullYear() + "https://stackoverflow.com/" + (date.getMonth() + 1) + "https://stackoverflow.com/" + (date.getUTCDate());
(date.getMonth is 0-indexed while date.getDate is 1-indexed but susceptible to time-zone differences.)
Fiddle: http://jsfiddle.net/GyC3t/25/