Javascript - Get Previous Months Date

Question

If i have a variable that returns a date, in the format of dd MMM yyyy, so 28 Aug 2014, how can i get the date of the previous month.

I can modify the month via:

Answer 1

Just subtract the number of months from the month parameter and don't worry if the value is going to be negative. It will be handled correctly.

new Date(2014, 0, 1) // 1st Jan 2014
new Date(2014, -1, 1) // 1st Dec 2013