Hello Rohit,
I got your message and use it for your requirement.
protected void Page_Load(object sender, EventArgs e)
{
const string someScript = "alertMe";
if (!ClientScript.IsStartupScriptRegistered(this.GetType(), someScript))
{
ClientScript.RegisterStartupScript(this.GetType(),
someScript, "alert('I was called from Content page!')", true);
}
}