JS Dapatkan hari pertama dan terakhir bulan sebelumnya

var d = new Date();
d.setDate(0); //sets d to the last day of the previous month
d.setDate(1); //sets d the the first day of that month
d.setHours(0,0,0,0); //sets d time to midnight

//d now equals the first day of the month before today      
Lazy Lemur