How would I view console log of this code?

I'm trying to fix an issue as stated in a previous stack overflow but I'm not getting any replies, so I'm trying to figure it out myself anyway...

How would I view console data from this code, so I can see exactly what heights are being calculated?

window.onscroll = function (event) {
   var offset = window.pageYOffset;
   var wheight = window.innerHeight;
   var html = document.documentElement;
   var docheight = Math.max(document.body.scrollHeight, document.body.offsetHeight,
   html.clientHeight, html.scrollHeight, html.offsetHeight);
   var progress = offset / wheight;

   document.getElementById("SVGID_1_").setAttribute("y1", 93000 + progress * 93000);
}

jsfiddle here: http://ift.tt/1ynAB5B