Get number days in a specified month using javascript?

Question

Hi,

Title says it all.

Say I have the month as a number and a year.

Malcolm

Answer 1

function daysInMonth(Month, Year)
 {
     return 32 - new Date(Year, Month, 32).getDate();
 }

    daysInMonth(7,2009)
>>> 31

Answer 2

function daysInMonth(month,year) {
    return new Date(year, month, 0).getDate();
}
daysInMonth(7,2009); //31
daysInMonth(2,2009); //28
daysInMonth(2,2008); //29

Answer 3

The following takes any valid datetime value and returns the number of days in the associated month... it eliminates the ambiguity of both other answers...

 // pass in any date as parameter anyDateInMonth
function daysInMonth(anyDateInMonth) {
    return new Date(anyDateInMonth.getYear(), 
                    ++anyDateInMonth.getMonth(), 
                    0).getDate();}

Answer 4

Date.prototype.monthDays= function(){
    var d= new Date(this.getFullYear(), this.getMonth()+1, 0);
    return d.getDate();
}

Answer 5

function daysInMonth(month,year) {
    return new Date(year, month, 0).getDate();
}

Have you tested the function for Feb 2012....it is a leap year and has 29 days...but the function shows 28 days...

Also u r welcome if you elaborate the New Date() and the format u r passing to it.....:)

Answer 6

Another possible option would be to use Datajs

Then you can do

Date.getDaysInMonth(2009, 9)

Although adding a library just for this function is overkill, it's always nice to know all the options you have available to you :)