How do you call a client side javascript callback method after an
update panel has posted back to the server?

I have two update panels (A + B) with a gridview in each panel.

GridView B has a Trigger to listen when GridView A posts back from a
Select button. This works fine. I can get the Postback from GridView B
and I am able to update formatting of GridView B in it's PreRender
Event.

Gridview B has textboxes open in it's Item Template Mode. I can add an
attribute that to select the data when a user clicks on a textbox.
However, I was not able to call the Microsoft SetFocus event for a
newly added textbox when a new row was added from the RowUpdating
event in GridView A.

(this works fine)
----------------------------------------------------------------------------------------------------------
CType(gridRow.Cells(4).FindControl("txtRecipientAmount"),
TextBox).Attributes.Add("onfocus", "javascript:select();")

If I use the SetFocus method, it will work when the page posts back,
but not the Update Panel.

(this will work with a page post back, but not when the UpdatePanel
posts back)
----------------------------------------------------------------------------------------------------------------
CType(gridRow.Cells(4).FindControl("txtRecipientAmount"),
TextBox).Focus()

What I would like to do is call a javascript method on the client
after UpdatePanel B has been fired. How do I do this?

Thanks for the help,
Gabe