[javascript] Get first and last date of current month with JavaScript or jQuery

As title says, I'm stuck on finding a way to get the first and last date of the current month with JavaScript or jQuery, and format it as:

For example, for November it should be :

var firstdate = '11/01/2012';
var lastdate = '11/30/2012';

I fixed it with Datejs

This is alerting the first day:

var fd = Date.today().clearTime().moveToFirstDayOfMonth();
var firstday = fd.toString("MM/dd/yyyy");
alert(firstday);

This is for the last day:

var ld = Date.today().clearTime().moveToLastDayOfMonth();
var lastday = ld.toString("MM/dd/yyyy");
alert(lastday);