Using robert penners easing to animate dom elements

Question

Im having some trouble understanding how this works. I have read the tutorial on robert penners website where the different parameters are explained:

t: time b: start value c: change d: duration

I have specified the values but it doesnt seem to work, why is that? I dont seem to get the elastic effect but more of a single stop somewhere at the start.

https://jsfiddle.net/m1qzqvu8/4/

var elem = document.getElementsByTagName('div')[0]

function fn(){
  var x = parseInt(elem.style.left);
  if(x < 200) {
    x += easeOutElastic(0, 10, 100, 4)
    elem.style.left = x + "px"
  }
    requestAnimationFrame(fn)
}

fn()

function easeOutElastic (t, b, c, d) {
        var s=1.70158;var p=0;var a=c;
        if (t==0) return b;  if ((t/=d)==1) return b+c;  if (!p) p=d*.3;
        if (a < Math.abs(c)) { a=c; var s=p/4; }
        else var s = p/(2*Math.PI) * Math.asin (c/a);
        return a*Math.pow(2,-10*t) * Math.sin( (t*d-s)*(2*Math.PI)/p ) + c + b;
    }