code: function(isDirty) {
        var t = this;
  
        // Pause a tour if the page turns dirty
        if (isDirty) {
          UI.pauseTour();
        }
  
        // Change the view elements
        t.$el.toggleClass('dirty', isDirty);
        if (!isDirty) {
          t.originalPage = t.model.toJSON({trim:false});
        }
      }
docs: Set the page as dirty or not