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codice:
<%@ Page Language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

    Protected Sub Button1_Click(sender As Object, e As System.EventArgs)
        Dim img As New WebControls.Image()
        img.ImageUrl = "http://static.panoramio.com/photos/original/216697.jpg"
        Me.PlaceHolder1.Controls.Add(img)
        
        Dim messaggio = "Ciao, Mondo!"
        Dim s As String = String.Format("$(window).load(function(event){{ alert(""{0}""); }})", messaggio)
        Me.ClientScript.RegisterStartupScript(Me.GetType, "alert", s, True)
    End Sub
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <script src="../js/jquery/jquery-min.js" type="text/javascript"></script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />
        


        <asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
    </div>
    </form>
</body>
</html>