ImageButton constructing OnClientClick String

Hi,
             I am not sure if I am expressing this correctly. I have a GridView, and an ImageButton Column (inside a ItemTemplate which is inside a TemplateField Column). I am attempting to construct the OnClientClick of the ImageButton and I cannot seem to get this to work. I am attempting:
 
<asp:ImageButton CommandName="Apply" OnClientClick='window.open("Application.aspx?JobType=1&TypeID=" + <%# DataBinder.Eval(Container.DataItem, "CraigSiteID")%>'
 
My problem is that the OnClientClick String is rendered literally.
 
Any ideas? Thanks in advance for your help,
O.O.
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