 Defining the user interface needs no HTML, and styling the interface needs no Cascading Style Sheets (CSS).Simple appearance themes are used to style colors, icons and other visual properties; they also support runtime switching..

qooxdoo uses a closed form to define new classes.The global class constructor takes two arguments, the name of the new class and a map that provides values for a set of predefined keys, like 'construct' (the constructor method hook), 'statics' (for static class attributes and methods), 'members' (for instance attributes and methods) and 'destruct' (for the destructor).