Why does comparing two dates that are exactly the same produce a false result?

I got two questions about JavaScript Date objects.

  1. I’ve created two date objects in my code and from all “appearances” they are the same values, yet, a comparison with the equality operator(==) returns the boolean value of false. Here they are as shown in Chrome’s JavaScript console:

Tue Mar 12 2013 18:10:56 GMT-0500 (Central Daylight Time)

Tue Mar 12 2013 18:10:56 GMT-0500 (Central Daylight Time)

Those were copied’n’pasted right out of the console. So I am confused on this one.

  1. Why do all my Date objects show a protype as “InvalidDate”. I have created date objects by simply calling the Date() constructor and they still have a prototype(actually proto if it matters) of “InvalidDate”. What’s up with this?

Thanks for all the help.

My first thought is try logging to the console with beginEditingLastUpdate.getTime() as this will give you a result accurate to the microsecond, instead of the iso-format string which is only displays with an accuracy of one second. I’d say there’s a difference between the two times but it’s less than one second.

I’m not sure why you’re seeing invalid date, however if you’re calling new Date() - ie with the new keyword and no arguments - it would certainly be unusual to see InvalidDate. If you’re calling new Date(some_value) please provide what some_value is.

edit: If you can provide the context of how you’re using yourdate.proto I may be able to better respond to part 2 of your question. As a guess, if you’re checking if an object is a date, try using

yourdate instanceof Date // returns true if yourdate is a Date object