code: function(mask) {
          var options = this.options,
              message;
  
          // Prepare mask
          mask.addClass('hide').appendTo(this.element);
  
          if (this.element.is('body')) {
              mask.css('position', 'fixed');
          }
  
          if (options.revealOnClick) {
              mask.click(this.hide.bind(this));
          }
  
          this.mask = mask;
  
          // Create message if it does not exist
          message = mask.find(this.ns('message'));
  
          if (!message.length && options.messageContent) {
              message = this.render(options.messageTemplate)
                  .html(options.messageContent)
                  .appendTo(mask);
          }
  
          this.message = message;
      }
docs: Set the element to use as a mask and append it to the target element.
  Apply optional classes, events, and styles dependent on implementation.
  
  @param {jQuery} mask