Delete function will get the selected id(s) and create JSON data and send JSON data to Java server-side for handle.

/************************************************************
    * Action - delete
    *   start to handle delete function
    *   need confirm to delete
    ************************************************************/	
    function doDel(){
        var m = grid.getSelections();
        if(m.length > 0)
        {
        	Ext.MessageBox.confirm('Message', 'Do you really want to delete it?' , doDel2);	
        }
        else
        {
        	Ext.MessageBox.alert('Message', 'Please select at least one item to delete');
        }
    }     
 
    function doDel2(btn)
	{
       if(btn == 'yes')
       {	
			var m = grid.getSelections();
			var jsonData = "[";
	        for(var i = 0, len = m.length; i < len; i++){        		
				var ss = "{\"id\":\"" + m[i].get("id") + "\"}";
				//alert(ss);
				if(i==0)
	           		jsonData = jsonData + ss ;
			   	else
					jsonData = jsonData + "," + ss;	
				ds.remove(m[i]);								
	        }	
			jsonData = jsonData + "]";
			ds.load({params:{start:0, limit:myPageSize, delData:jsonData}});		
		}
	}

And delete parameter to server side with JSON data like this: delData=[{"id":"5"},{"id":"6"}]