从vb.net后面的代码调用javascript

Question

What I'm trying to do is to use javascript function to autoclick a button as method for error handling. The javascript work just fine with onClick on the button .The problem that I faced is that the javascript called does not work at all when I called it from the code behind. Am I doing it wrong?

here is my javascript:

<script type="text/javascript">
function callbtn() {
    document.getElementById("btnAlert").click();
}
 </script>

and here is the method that I used to call javascript from code behind:

If CheckLotIDExist = "Y" Then
 'do something here
Else
    LblMsg.Text = "Lot Not Foundzz!"
   ScriptManager.RegisterStartupScript(Page, Page.GetType, "script", "callbtn();", True)
End If

Answer 1

Try this:

 const string script = "function f(){callbtn(); Sys.Application.remove_load(f);}Sys.Application.add_load(f);";
 ScriptManager.RegisterStartupScript(Page, Page.GetType(), "keyLicDtlz", script, true);