Why is this include not working in jsp?

I want to conditionally include a css file in my jsp page based on some parameter:

<c:if test="${param.co == 'txmart'}">
    <link
        href="resources/css/txMart.css"
        rel="styleshee开发者_如何学Pythont"
        type="text/css" />
</c:if>

I cannot understand why this does not work... It always include txMart.css file...(even if co is null or having other value) Do you see any issue?

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The problem is that you didn't declare the use of the core taglib correctly. When using the classical JSP syntax, the use of a taglib must be declared like this:

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

The notation xmlns:c="http://java.sun.com/jstl/core" is used when the XML syntax is used. See http://download.oracle.com/docs/cd/B13597_05/web.904/b10320/jspxml.htm for details.