code: function(containerEl, attributeVal) {
        var AUTO_FOCUS = this.prefixer('md-autofocus', true);
        var elToFocus;
  
        elToFocus = scanForFocusable(containerEl, attributeVal || AUTO_FOCUS);
  
        if (!elToFocus && attributeVal != AUTO_FOCUS) {
          // Scan for deprecated attribute
          elToFocus = scanForFocusable(containerEl, this.prefixer('md-auto-focus', true));
  
          if (!elToFocus) {
            // Scan for fallback to 'universal' API
            elToFocus = scanForFocusable(containerEl, AUTO_FOCUS);
          }
        }
  
        return elToFocus;
  
        /**
         * Can target and nested children for specified Selector (attribute)
         * whose value may be an expression that evaluates to True/False.
         */
        function scanForFocusable(target, selector) {
          var elFound, items = target[0].querySelectorAll(selector);
  
          // Find the last child element with the focus attribute
          if (items && items.length){
            items.length && angular.forEach(items, function(it) {
              it = angular.element(it);
  
              // Check the element for the md-autofocus class to ensure any associated expression
              // evaluated to true.
              var isFocusable = it.hasClass('md-autofocus');
              if (isFocusable) elFound = it;
            });
          }
          return elFound;
        }
      }
docs: Finds the proper focus target by searching the DOM.
  
  @param containerEl
  @param attributeVal
  @returns {*}