The World-Wide Web offers a potentially interesting tool to collect data from a large and heterogeneous audience. While questionnaires have become rather common on the Internet, its potential reaches far beyond text processing. In principle, it is possible not only to perform interactive, dynamic experiments on the Web, but also to include graphical animation and time-critical responses, such as reaction times. We implemented a visual motion extrapolation task on the Web using the programming language Java, which can be interpreted by standard Web browsers such as Netscape or Internet Explorer. The data collected with this method turned out to be reliable and differed little from data obtained in a controlled laboratory setting, with the exception of conditions with fixation instruction. Thus, the Web can, generally speaking, be used for data collection of large sample sizes. The strengths and weaknesses of dynamic visual simulation experiments on the Internet are discussed.