Minimal webp support check addition to Modernizr

webp.modernizr.js

(function (document) {
  'use strict';
  var webpImg = new Image();
  webpImg.onerror = function() {
    setModernizr(false);
  }
  webpImg.onload = function(){
    var root = document.getElementsByTagName('html')[0];

    if (root.classList) {
      root.classList.add('webp');
    } else {
      root.className += ' webp';
    }
    setModernizr(true);
  };
  webpImg.src = 'data:image/webp;base64,UklGRjIAAABXRUJQVlA4ICYAAACyAgCdASoBAAEALmk0mk0iIiIiIgBoSygABc6zbAAA/v56QAAAAA==';


  function setModernizr(support) {
    Modernizr.addTest('webp', function(){
      return support;
    });
  }

})(document);