This question is purely to satisfy my curiosity.
In the JavaScript Date object, when you call getMonth() it returns the month but it counts from 0.
0 = January
1 = February
...
But when you call getDate() it starts counting from 1
1 = 1
2 = 2
...
Why the inconsistency?
I assume it's because it would be easier to reference in an array of names, i.e.
var months = [January, February, March, April, May, June, July,
August, September, October, November, December];
var d = new Date();
var namedMonth = months[d.getMonth()];
If getMonth() returned 1-12, then programmers would have to do d.getMonth()-1 everytime they wanted a fancy named month.
Days of the month don't have specific names per se. The getDate() returns 1-(28-31). We usually just refer to them by their number.
The same concept as getMonth() applies for getDay() also, which returns 0-6 based on the day of the week
var days = [Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday];
var namedDay = days[d.getDay()];
All this returns something like:
console.log(Month: month[ + d.getMonth() + ]: + namedMonth);
//Month: month[3]: April
console.log(Day: days[ + d.getDay() + ]: + namedDay);
// Day: days[4] : Thursday
