To use the Struts-EL tags, you need to use the following files from the Struts distribution:
struts.jar struts-el.jar struts-*-el.tld
As explained in the contrib/struts-el/README.txt file, the struts.jar is still needed because the struts-el tag library classes are subclasses of the struts tag library classes.
There are a number of examples you can find for using these tags in the strutsel-exercise-taglib.war found in the current Struts distribution.
The struts.jar is still required by the struts-el.jar because struts-el classes extend struts classes. The struts-el tag library classes have the added capability of knowing how to evaluate EL expressions, e.g. "${zoektype.waarde}". The regular struts tag library classes do not evaluate EL.
With a little knowledge, a cast iron skillet is non-stick and lasts a lifetime.