Call Master Page JavaScript function from Code behind on Timer Tick event in ASP.Net

not able to call javascript function from codebehind on timer tick event of master page

protected void Timer1_Tick(object sender, EventArgs e)
{
    ScriptManager.RegisterStartupScript(this, typeof(Page), "Alert", "showpop('" + "Description" + "','" + "Title" + "')", false);
}

<script type="text/javascript">
    function showpop(msg, title) {
        alert("ok");
    }
</script>