text: document.addEventListener('DOMContentLoaded', function() {
  
    var wrapper = document.getElementById('wrapper');
    var topLayer = wrapper.querySelector('.top');
    var handle = wrapper.querySelector('.handle');
    var skew = 0;
    var delta = 0;
  
    if (wrapper.className.indexOf('skewed') != -1) {
      skew = 1000;
    }
  
    wrapper.addEventListener('mousemove', function(e){
      delta = (e.clientX - window.innerWidth / 2) * 0.5;
  
      handle.style.left = e.clientX + delta + 'px';
  
      topLayer.style.width = e.clientX + skew + delta + 'px';
  
    });
  
  });
  