I have what is probably a simple syntactical problem. As background, the button is in a nested ListView, but it seems like it should be pretty straightforward. The js function simply takes the TripID variable and opens a popup window with the data. The error message is that the server tag is not well formed which makes me think it is a matter of quotes and single ticks but I'm not having any luck finding an example of how best to fix this. Thanks for the help.
<asp:LinkButton ID="btnRegistered" runat="server" Text="See Who Has Registered" CssClass="readmore" OnClientClick="listWindowOpen('<%# Eval("TripID") %>');return false;" UseSubmitBehavior="False" />