Radio button

Hello Everyone,
I am trying to create different search methods using radio buttons. This is a web app. using asp.net and vb.net
1)Radio Button 1 - search by Account Number - txtAccountNumber
2)Radio Button 2 - search by Customer Last and First Name - txtLastName, txtFirstName
3) Radio Button 3 - search by Customer ZipCode - txtZipcode
One search button - btnSearch
By default, the search button is aligned to the txtAccountNumber (next to txtAccountNumber)
If option 2 is selected, the search has to align to txtLastName, and other txtboxes are visibly disabled
If option 3 is selected, the search has to align to txtZipcode. and txtboxes are visibly disabled

I tried the followings, but it did not work.
Protected Sub rbSearchZipcode_CheckedChanged(ByVal sender As Object, ByVal e As EventArgs) Handles rbSearchZipcode.CheckedChanged

txtAccountNumber.visible = false
txtLastName.visible = false
txtFirstName.visible = false
btnSearch.visible= true

txtZipcode.top = btnSearch.top ' this worked for windows form, but not for web form.

End Sub

Would you please give me some advice on how to achieve this?
Thank you very much!