code: function focusOnOpen() {
          if (options.focusOnOpen) {
            var target = $mdUtil.findFocusTarget(element) || findCloseButton() || dialogElement;
            target.focus();
          }
  
          /**
           * If no element with class dialog-close, try to find the last
           * button child in md-actions and assume it is a close button.
           *
           * If we find no actions at all, log a warning to the console.
           */
          function findCloseButton() {
            return element[0].querySelector('.dialog-close, md-dialog-actions button:last-child');
          }
        }
docs: For alerts, focus on content... otherwise focus on
  the close button (or equivalent)