Set/get nested grid properties inside a grid

1

i have two grids control (gridA, gridB) , i am nested gridB into gridA

 for u=0 to 3
    gridA.setValue(u,0,"Title No " & u)
    gridA.setRowHeight(u,"45px")
    gridA.cell(u,0).style.fontSize="22px"
next
gridA.refresh()
For u=0 To 5
      gridB.setValue(u,0,"&nbsp&nbsp&nbsp Sub Title " & u)
      gridB.setRowHeight(u,"30px")
      gridB.cell(u,0).style.fontSize="17px"
      gridB.cell(u,0).style.backgroundColor="transparent"
Next
gridB.refresh()
clone=gridB.cloneNode(True)
clone.id="gridB_1" 
NSB.$("gridA_1_0").appendChild(clone)  'nested  into gridA row 1, col 1
NSB.$("gridB_1").style.display="block"   'show the gridB in gridA cell
clone.addEventListener("mousemove",gridBmm) 

Function gridBmm(event)
  If event=undefined Then Exit Function
  If event.target.id="" Then Exit Function
  s=Split(event.target.id,"_")
  for n=0 to NSB.$("gridB_1").getRowCount()  - 1 ' cause error , NSB.$("gridB_1").getRowCount() is not a function 
      ....
  next
End Function

question:

  1. how can i get the object reference(gridB_1) in gridBmm function
  2. can i pass extra paramaters into gridBmm function together with ‘event’ paramater