IsPostBack issues

[Pradeep1210]

I have this code on my asp.net page in page load event:

If Not IsPostBack Then
    recordId = Request.QueryString("rid")
    myRecord = GetRecord(recordId)
    If myRecord Is Nothing Then
        ShowErrorMessage("Record not found!") 
        ' pnlMainBody.Visible = False
        Exit Sub
    End If
    ViewState("RecordId") = recordId
Else
    recordId = ViewState("RecordId").ToString
End If

and this javascript code:

function GotoRecord() {
    var tb = document.getElementById('txtRecordNumber');
    if (isNaN(tb.value) || tb.value.indexOf('.') >= 0) {
        tb.focus();
        alert("Enter valid Record Number.");
    }
    else
        window.location = 'ShowRecord.aspx?rid=' + tb.value;
}

It works fine until the "pnlMainBody.Visible = False" is commented out and shows the message ""Record not found!" correctly. But if I uncomment that line, it believes that it is a postback and enters the ELSE block and errors out, when user enters some record number in the textbox and hits enter (it executes the javascript code)

Any ideas?