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                (function() {
  'use strict';

  // throttled value before window event starts
  var throttled; 
  // Delay function calls to 66ms (frame rate: 15fps)
  var delay = 66; 
  // Declare empty variable for later use
  var resizeTimeout;

  // Grab body element
  var body = document.querySelector('body');
  // Create element
  var viewportDimensions = document.createElement('div');

  // Style element = 'fixed'; = 0; = 0; = '16px'; = 3; = '22px';

  // Add div element inside body element

  // window.resize callback function
  function getViewportDimensions() {
    var width = window.innerWidth;
    var height = window.innerHeight;

    viewportDimensions.textContent = width + 'px' + ' x ' + height + 'px'; = 'block';

    resizeTimeout = setTimeout(removeViewportDimensions, 3000);

  // Called from getViewportDimensions()
  function removeViewportDimensions() { = 'none';

  function throttler() {
    // Only run code if’s block if we’re not throttled
    if (!throttled) {
      // Callback: the function we want to throttle
      // We're currently throttled!
      throttled = true;
      // Reset throttled variable back to false after delay
      setTimeout(function() {
        throttled = false;
      }, delay);

  // Listen to resize event, and run throttler()
  window.addEventListener('resize', throttler);

  // End of IFFE wrapper