get first day of a month javascript code example

Example 1: javascript get current month start and end date

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

Example 2: get last date of a month javascript

var lastday = function(y,m){
return  new Date(y, m +1, 0).getDate();
}
console.log(lastday(2014,0));
console.log(lastday(2014,1));
console.log(lastday(2014,11));