who_is_breaking_the_layout.js

var all = document.getElementsByTagName('*');
var max = window.innerWidth;

for (var i = 0; i < all.length; i++) {
  var el    = all[i];
  var width = all[i].offsetWidth;

  if (width <= max) {
    continue;
  }

  console.log({
    el   : el,
    width: width
  });
}