I have aspx pages which uses repetative code. So i put them on a masterfile and referring that in all other files. I have used the in all other pages where i included maste
To not append the Container's ID to the control's id, set the ClientIDMode="Static" property of the control.
<input id='chkRaces_1' type='checkbox' ClientIDMode="Static" runat='server' onclick="enableShow50();" /><
You can use ClientIDMode, but keep in mind that's only available in .NET 4.0 and above.
<asp:Label ID="SelectedSport" runat="server" ClientIDMode="Static">
</asp:Label>
Or in JavaScript:
var userLabel = document.getElementById('<%=SelectedSport.ClientID%>');
if you are trying to access the control in javascript, then using .ClientID is probably your best bet, as it doesn't require change in aspx page