Use
<input type="hidden" name="lblerrorMessage" id="lblerrorMessage" runat="server" value="" />
I think Onchange
callme();
method should be remove. Its should be call from after Upload sucessfully
if (Ismatch == true)
{
lblerrorMessage.Value = "Valid Document";
ClientScript.RegisterStartupScript(GetType(), "Javascript", "javascript:callme();", true);
}
else
{
lblerrorMessage.Value = "Not a Valid Document";
ClientScript.RegisterStartupScript(GetType(), "Javascript", "javascript:callme(); ", true);
return;
}