How to fire JS from code behind of a UserControl by an event

Question

In ASP.NET C#, I want to show an ALERT(\'HI\') from codebehind of a UserControl but doesn\'t work:

User Control:

Answer 1

there may be below possible reasons try to change these and check it works or not

 1). ScriptManager.RegisterStartupScript(this, this.GetType(), "msg", "alert('hi!')", true);//no need to use javascript with alert when bool set to true

 2). ScriptManager.RegisterStartupScript(page, page.GetType(), "msg", "alert('hi!')", true);

 3). ClientScript.RegisterClientScriptBlock(GetType(), "sas", "<script> alert('hi!');</script>", true);