Register java script variable from server side

protected void Page_Load(object sender, EventArgs e)

{

   Int16 userId = 1;

   Page.ClientScript.RegisterStartupScript(this.GetType(), "UserId", "<script> var UserId=" + userId + "</script>");

}

In the above code, variable UserId is initialized by value 1 and we can access this value in client side.

<script type="text/javascript" language="javascript">

    $(document).ready(function () {

            GetServerSideValue();

        });

         function GetServerSideValue() {

            alert(UserId);

        }

</script>