A XHTML component generates attributes directly to native HTML tags. It means, unlike XUL, it doesn't prefix the servlet context path to attributes for specifying URL. For example, the following codes don't work (unless the servlet context is "").

<img href="/my/good.png"/>

Rather, you shall use the encodeURL function in EL expressions as follows.

<?taglib uri="http://www.zkoss.org/dsp/web/core.dsp.tld" prefix="p"?>
...
<img href="${p:encodeURL('/my/good.png')}"/>

In Java, you shall use the encodeURL method from org.zkoss.zk.ui.Execution.

<img id="another"/>
<zscript>
another.setDynamicAttribute("href",
Executions.getCurrent().encodeURL("/my/good.png"));
</zscript>

Notice that XUL components and all ZK features that accept an URL will invoke the encodeURL method automatically^[6].