Mirror scrolling of 2 differently sized HTML elements

gistfile1.js

function mirrorScroll(el1, el2) {
  var el1TotalHeight = el1[0].scrollHeight;
  var el2TotalHeight = el2[0].scrollHeight;
  var totalHeightRatio = el2TotalHeight / el1TotalHeight;

  var el1WindowHeight = el1.height();
  var el2WindowHeight = el2.height();
  var windowHeightRatio = el2WindowHeight / el1WindowHeight;

  var el1PixelsScrolled = el1.scrollTop();
  var el1PercentageScrolled = (el1PixelsScrolled / el1TotalHeight) * 100;

  var el2PercentageToScroll = (el1PercentageScrolled * totalHeightRatio);
  var el2PixelsToScroll = (el2TotalHeight / 100) * (el2PercentageToScroll * windowHeightRatio);

  el2.scrollTop(el2PixelsToScroll);
}