javascript fá núverandi degi mánuði
new Date().getDate();//gets day of month (1-31)
javascript degi fyrsta daginn af núverandi mánuð
var date = new Date();
var firstDay = new Date(date.getFullYear(), date.getMonth(), 1);
var lastDay = new Date(date.getFullYear(), date.getMonth() + 1, 0);