creating a resizablecontrolextender from code behind

hi i trying to create a Resizablecontrol extender from code behind.

everything works fine including css and others.

but when i tried to add

oncliendresizing

it is not working. i cant just add the javascript function name to the control

 Dim rs As New ResizableControlExtender

 rs.TargetControlID = label.ID
        rs.ID = label.Text & 66
        rs.HandleCssClass = "handlecss"
        rs.ResizableCssClass = "resizablecss"

        rs.OnClientResize("onResize")
'onResize is my javascript function
'i am having error for this line of code.
'wat should i put in this?he is asking for index as char.
        rs.MinimumHeight = 30
        rs.MinimumWidth = 20
        rs.HandleOffsetX = 0
        rs.HandleOffsetY = 0