javascript - Maintain Scroll Position of ASP Listbox Inside an ASP Update Panel -

i have 4 asp listboxes inside of 1 asp updatepanel. website webforms project using vb.net. these listboxes acting filter database table. when click on first listbox, updates remaining listboxes relevant selection. can multi-select items inside these listboxes. important.

the problem occurs scroll position of listboxes resetting top when select multiple items. select top item, , scroll down 14th item , ctrl + click select both. causes scroll position of listbox reset top after partial postback caused update panel filtering remaining listboxes. can imagine, can annoying clients.

i've seen other solutions maintaining scroll position of update panel, not controls inside update panel. ideas?

i answered own question. did leveraged trigger functionality of update panels , enclosed last 3 listboxes own update panel.

the first listbox doesn't need in update panel because contents don't have change depending on selections of rest of listboxes' contents. second listbox enclosed in own update panel, , added asynchronous post trigger first listbox. third , fourth listboxes, enclosed them in own update panels, , added asynchronous triggers each of preceding controls respectively (so on third listbox update panel, added 2 asynchronous triggers preceding controls, , 3 asynchronous preceding controls on 4th listbox update panel).

hope helps else!