How to insert the ClientID of a div into an OnClientClick event

In the XHTML for a page I have:-

<asp:Button ID="bookNowButton" runat="server" CssClass="bookNowButton"
            OnClientClick="showHideLoggedInDiv('<%=bookingFormDiv.ClientID%>')" />

This breaks. I need开发者_Python百科 the correct syntax or method to insert the bookingFormDiv.ClientID into the control.

What needs to be done?

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You can set the attribute from code behind:

bookNowButton.OnClientClick = "showHideLoggedInDiv('" + bookingFormDiv.ClientID + "')"

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As this is the correct syntax i would start looking elsewhere, what is bookingFormDiv, is it server side control (runat=server) with the id bookingFormDiv?

edit

realised this is within a server side control (asp:Button) so you cannot use that syntax, the accepted answer is correct.

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Remove runat="server", then replace asp:Button with input type="button" and OnClientClick with onclick.