how to use javascript in asp.net

this code i hav written in page head section??????????/ in this sectoin
<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server"/>
-----------------------------JAVASCRIPT IS AS FOLLOWS----------------------
<script type="text/javascript"language="javascript">
function validate()
{
var Firstname = document.getElementById('<%=txtname.ClientID %>').value;
if (Firstname == "")
{
alert("Enter First Name");
document.getElementById("<%=txtname.ClientID%>").focus();
return false;
}
</script>
--------------------------------------------------
-<asp:Button ID="btnregister" runat="server"
Text="Register" OnClientClick=" return validate();"
onclick="btnregister_Click"/>