Almost any application has some hierachically organized data. JTree is our solution how to represent it. JTree is a light-weight (only 50 Kb's) applet based on AWT, which runs on Java 1.1. Therefore the applet works in browsers Netscape and Ineternet Explorer since versions 4.x and any JRE. Applet supports dynamical loading from server (to minimize amount of data transferred on start-up) and loading from XML and XML stream. Any background, icons, drop-down menus, insert/edit/delete items dynamically using JavaScript, event handlers provided for OnClick, OnDoubleClick events, so it is possible to execute custom JavaScript code upon this events.