code: function loadFunction (js, resolver) {
          immediate(function () {
              try {
                  js.call(null, resolver);
              }
              catch (e) {
                  resolver.reject(e);
              }
          });
      }
docs: @private
  @name loadFunction
  Loads JS function or script string for
  browser that does not support Data URI
  
  @param {String|Function} js
  @param {Function} fn