if (!document.getElementsByClassName) {

     document.getElementsByClassName = function(className, element) {

         var children = (element || document).getElementsByTagName('*');

         var elements = new Array();

         for (var i = 0; i < children.length; i++) {

             var child = children[i];

             var classNames = child.className.split(' ');

             for (var j = 0; j < classNames.length; j++) {

                 if (classNames[j] == className) {

                     elements.push(child);

                     break;

                 }

             }

         }

         return elements;

     };

 }