javascript calculate date minus days code example

Example 1: javascript today minus 1 day

var d = new Date();
 d.setDate(d.getDate()-1);

Example 2: 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 3: js date minus 18 years

use moment.js