You should repeat the steps a-b mentioned above, and instead of ExtJS's you can use native dhtmlxgrid style of initialization:

   var panel=new Ext.grid.dhxGridPanel({    //define panel
          height:350,
          title:'Some Grid'
      });
      panel.render('grid-example');               //render panel
      var grid=panel.grid;                        //take grid instance
 
 
 
      grid.setHeader("Name,Index,Code");
      grid.setInitWidths("150,150,*")
      grid.setColAlign("left,left,right")
      grid.setColTypes("ro,ro,ro");
      grid.init();
      grid.enableSmartRendering(true);
      // loading 50000 rows dataset
      grid.loadXML("../../../../main/dhtmlxgrid/samples/!!loading_big_datasets/50000_load_grid.php?un="+Date.parse(new Date()));