Disabling Submit Button

[Fishcake]

I'd like to disable a submit button to prevent mutiple database entries.
I've not had a problem disabling the button using Javascript but the method i used seems to intercept the postback and so the normal code is never executed. I found out i had to manually post the form, with this the form is submitted and page_load runs but i still can't get the button_onclick event to run after the button is disabled. code.....

'In code behind
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    If Not IsPostBack Then
        btnSubmit.Attributes.Add("onclick", "return disableMe(this);")
    End If
End Sub
 
Sub btnSubmit_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnSubmit.Click
    'Fairly long process here
End Sub
 
'In Script in .aspx file
        <script language="javascript">
            function disableMe(btn) {
                btn.disabled = true;
                document.form1.submit();
                return true;
            }
        </script>

I've found quite a few examples on the web but couldn't get any of them to work.

any ideas?