Got it after few hours. 

//Change to next row and update value 

          function js_AfterUpdate(grid, cell)
                {  
                var grid = igtbl_getGridById(grid);  
                var cell = igtbl_getCellById(cell);  
                var aRow = cell.getRow();  

//Update value
                if(cell.getValue()!=0 && cell.getValue()){  
//problems with ','
                   var val1 = aRow.getCell((cell.Index)-2).getValue().replace(',','.');
//problems with ','
                   if(val1==0)val1 = aRow.getCell((cell.Index)-1).getValue().replace(',','.');
//Add new value
                   aRow.getCell(cell.Index+1).setValue(val1/cell.getValue());}
        
                aRow = aRow.getNextRow(true); 
//cursor moves one to te left so right index is current index - 1                
                var aCell = aRow.getCell(cell.Index-1);  
                if(aCell)aCell.activate();  
                }

ps. how can you delete your own post?