JSFiddle - React, Tailwind, and code Playground
by dirtyd77
HTML
<span id="date"></span>
JavaScript
var d1 = new Date(2012, 1, 6) // date(year, month - 1, day)
days= -90; //# of days
var d2 = new Date(d1.setDate(d1.getDate() + days));
document.getElementById('date').innerHTML = d2;