guardate questo script (da vs net)

codice:
<html> 
<head> 
<script language="VB" runat="server"> 
public Sub Page_Load(Sender As Object,e As EventArgs) 


' Form the script to be registered at client side. 
Dim scriptString As String = "<script language=JavaScript> function DoClick() {" 
scriptString += "showMessage2.innerHTML='<h4>Welcome to Microsoft .NET!</h4>'}" 
scriptString += "function PageLoad(){ showMessage1.innerHTML=" 
scriptString += "'<h4>RegisterStartupScript Example</h4>'}<" 
scriptString += "/" 
scriptString += "script>" 

If(Not Me.IsStartupScriptRegistered("Startup")) Then 
Me.RegisterStartupScript("Startup", scriptString) 
End If 
Response.write("-------" & showMessage1.innerHTML) 
End Sub 
</script> 
</head> 
<body topmargin="20" leftmargin="10" onLoad="PageLoad()"> 
<form id="myForm" runat="server"> 
<span id="showMessage1" runat="server"></span> 

 
<input type="button" value="ClickMe" onclick="DoClick()"> 

 
<span id="showMessage2"></span> 


</form> 
</body> 
</html>
con Response.write("-------" & showMessage1.innerHTML) verifico il testo .. ed effettivamente il testo di showMessage1 è vuoto..

invece io voglio ke ciò nn accada .. ciò ke prima del page_load ci sia lo script js .. come faccio?