How to close asp.net window?

I want to write code behind by close button so when user click rhat button whole application is close... is it possible?

//this code is not giving right result...
protected void ImageButton3_Click(object sender, ImageClickEventArgs e)
    {

       Response.Write("<script language='javascript'>window.open('','_self',''); window.close();</script>");
       // Response.Write("<script language='javascript'>self.close();</script>");
        //Response.Write("<script language='javascript'> { self.close() }</script>");

       //Me.ClientScript.RegisterClientScriptBlock(Me.GetType(), "closemyself", "<script>self.close();</script>");


    }