cssom.js

(function(global) {
  'use strict';

  if (!('window' in global && 'document' in global))
    return;

  //----------------------------------------------------------------------
  //
  // CSSOM View Module
  // https://dev.w3.org/csswg/cssom-view/
  //
  //----------------------------------------------------------------------

  // Fix for IE8-'s Element.getBoundingClientRect()
  if ('TextRectangle' in global && !('width' in global.TextRectangle.prototype)) {
    Object.defineProperties(global.TextRectangle.prototype, {
      width: { get: function() { return this.right - this.left; } },
      height: { get: function() { return this.bottom - this.top; } }
    });
  }
}(self));