Polyfill for Element.getElementsByClassName(search)

Element.getElementsByClassName.polyfill.js

if (!Element.prototype.getElementsByClassName) {
  Element.prototype.getElementsByClassName = function (search) {
    var d = this, elements, pattern, i, results = [];
    if (d.querySelectorAll) { // IE8
      return d.querySelectorAll("." + search);
    }
    if (d.evaluate) { // IE6, IE7
      pattern = ".//*[contains(concat(' ', @class, ' '), ' " + search + " ')]";
      elements = d.evaluate(pattern, d, null, 0, null);
      while ((i = elements.iterateNext())) {
        results.push(i);
      }
    } else {
      elements = d.getElementsByTagName("*");
      pattern = new RegExp("(^|\\s)" + search + "(\\s|$)");
      for (i = 0; i < elements.length; i++) {
        if (pattern.test(elements[i].className)) {
          results.push(elements[i]);
        }
      }
    }
    return results;
  }
}