REQUESTING A THE CURRENT PAGE FROM JAVA SCRIPT WITH QUERY STRING

window.location.href=window.document.URL+'?search_str=' + $get('search_q_Header').value + '&search_type=' + searchType;

THIS ABOVE STATEMENT REQUEST THE CURRENT PAGE AS A NEW REQUEST NOT AS A POSTBACK

ACCESSING THE QUERYSTRING VALUES FROM THE PAGELOAD

If Not IsPostBack Then
                If Not Request.QueryString("search_str") Is Nothing Then
                    search_text = Request.QueryString("search_str").ToString()
                    search_type = Request.QueryString("search_type").ToString()
                    Search()
                End If
            End If