JavaScript сегодня минус 1 день
var d = new Date();
d.setDate(d.getDate()-1);
Ham-Solo
var d = new Date();
d.setDate(d.getDate()-1);
var myCurrentDate=new Date();
var myPastDate=new Date(myCurrentDate);
myPastDate.setDate(myPastDate.getDate() - 8);//myPastDate is now 8 days in the pastuse moment.js