JAVASCRIPT

javascript first and last day of the month

var date = new Date(), y = date.getFullYear(), m = date.getMonth();
var firstDay = new Date(y, m, 1);
var lastDay = new Date(y, m + 1, 0);

js get first and last day of previous month

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