javascript get days since date code example

Example 1: javascript subtract days from date

var myCurrentDate=new Date();
var myPastDate=new Date(myCurrentDate);
    myPastDate.setDate(myPastDate.getDate() - 8);//myPastDate is now 8 days in the past

Example 2: new date() in javascript 3 days from now

var dt = new Date();
dt.setDate(dt.getDate() + 3);