if (!cs.IsClientScriptBlockRegistered(cstype, csname2))
{
StringBuilder cstext2 = new StringBuilder();
cstext2.Append("<script type=text/javascript> function DoClick() {");
cstext2.Append("Form1.Message.value='Text from client script.'} </");
cstext2.Append("script>");
cs.RegisterClientScriptBlock(cstype, csname2, cstext2.ToString(), false);
}

protected override void OnPreRender(EventArgs e)
{
base.OnPreRender(e);
Page.ClientScript.RegisterClientScriptResource(typeof(MyControl), "Controls.Resources.Script_include.js");

}