JTidy *: Tag Library comes with 2 different tlds at the moment. Look at this table to understand which is the right one for you.

jtidy-taglib-11.tldhttp://jtidy.sf.netJsp 1.1 version of the tld, you will need to use this one if you plan to install your application on container only supporting j2ee 1.2 (Tomcat 3, Websphere 4, WebLogic 6...).
jtidy-taglib-12.tldhttp://jtidy.sf.netJsp 1.2 version of the tld: requires j2ee 1.3 (Tomcat 4, WebSphere 5, WebLogic 7...). Use this version if you are not looking for j2ee 1.2 compatibility.