Sets the month value in the Date object using local time.
To set the month value using Universal Coordinated Time (UTC), use the setUTCMonth method.
If the value of numMonth is greater than 11 (January is month 0) or is a negative number, the stored year is modified accordingly. For example, if the stored date is "Jan 5, 1996" and setMonth(14) is called, the date is changed to "Mar 5, 1997."
The setFullYear method can be used to set the year, month, and day of the month.
Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards, Internet Explorer 10 standards. Also supported in Windows Store apps. See Version Information.