Find first day of previous month in javascript

Question

Given a date object, how to get its previous month's first day in javascript

Answer 1

function firstDayInPreviousMonth(yourDate) {
    var d = new Date(yourDate);
    d.setDate(1);
    d.setMonth(d.getMonth() - 1);
    return d;
}

EDIT: Alright... I've definitely learned something here. I think that this is the simplest solution that covers all cases (and yes, it does work for January):

function firstDayInPreviousMonth(yourDate) {
    return new Date(yourDate.getFullYear(), yourDate.getMonth() - 1, 1);
}