DayOfWeek today = DateTime.Today.DayOfWeek;
if (today == DayOfWeek.Sunday || today == DayOfWeek.Saturday)
{
ClientScript.RegisterStartupScript(GetType(), "alert", "alert('" weekend"');", true);
}
else
{
ClientScript.RegisterStartupScript(GetType(), "alert", "alert('" weekday"');", true);
}