The fifteenth of February isn't found

Question

I'm in javascript, running this in the console

d = new Date();             
d.setMonth(1);
d.setFullYear(2009);
d.setDate(15);                                  
d.toString();

outputs this:

"Sun Mar 15 2009 18:05:46 GMT-0400 (EDT)"

Why would this be happening? It seems like a browser bug.

Answer 1

That's because when you initialize a new Date, it comes with today's date, so today is Oct 30 2008, then you set the month to February, so there is no February 30, so set first the day, then the month, and then the year:

d = new Date();
d.setDate(15);                    
d.setMonth(1);
d.setFullYear(2009);   

But as @Jason W, says it's better to use the Date constructor:

new Date(year, month, date [, hour, minute, second, millisecond ]);