javascript获取.net控件的ClientId

<script language="javascript" type="text/javascript">
        function show() {
            if (document.getElementById("<%=RBut1.ClientID%>").checked == true) {
                document.getElementById("<%=lblQueryID.ClientID%>").innerHTML = "RunIDs: ";
            }
            if (document.getElementById("<%=RBut2.ClientID%>").checked == true) {
                document.getElementById("<%=lblQueryID.ClientID%>").innerHTML = "RunQueryID: ";
            }
        }
    </script>
    <table border="0" style="width: 100%;">
        <tr>
            <td>
                We can use a Run Query ID or Runs' ID to serach the unanalyzed results for automation
                runs.<br />
            </td>
        </tr>
        <tr>
            <td>
                <asp:RadioButton ID="RBut1" runat="server" Text="RunIDs (e.g 937311;940816;940970)"
                    GroupName="W" Checked="True" onclick="show()" />
            </td>
        </tr>
        <tr>
            <td>
                <asp:RadioButton ID="RBut2" runat="server" Text="RunQueryID (e.g 156081)" GroupName="W"
                    onclick="show()" />
            </td>
        </tr>
        <tr>
            <td>
                <asp:Label ID="lblQueryID" runat="server" Text="RunIDs: " Font-Bold="True" Font-Size="Medium"></asp:Label>
            </td>
        </tr>
    </table>