Web-based study resources can be viewed as a basic requirement in order to remain a competitive player on a more and more globalised educational market. For that reason it is getting increasingly important for universities to supplement offered lectures with additional Web-based learning material. In this paper we focus on interactive multimedia elements like computer animations and simulations, which can be used by students for individual experimentation. Such supplementary material represents a motivating but also a very effective chance to deepen and to increase the knowledge acquired in the lecture. This paper gives some general guidelines for building interactive Web-based animations. Beyond that, two of our developed animations are presented in detail. The first animation visualizes the search processes of some common direct global and local optimization strategies. In the second animation an artificial ecosystem is simulated, where several autonomous agents have to perform a nu...