Here's a little script I got, and modified, from Charles Carroll, i think,
(
www.learnasp.com).
Public Shared Sub SetFocus(ByVal ControlClientID As String, ByVal Page
As System.Web.UI.Page)
Dim scriptFunction As New System.Text.StringBuilder
Dim scriptClientId As String
scriptFunction.Append("<script language='javascript'>")
scriptFunction.Append("document.getElementById('")
scriptFunction.Append(ControlClientID)
scriptFunction.Append("').focus();")
scriptFunction.Append("</script>")
Page.RegisterStartupScript("focus", scriptFunction.ToString())
End Sub
ControlClientID is the ClientID property of your control (likely a textbox).
Karl