Abstract
The present tutorial provides a technical overview of how to create web applications for online psychological experiments from scratch via the HTML/CSS/JavaScript framework. This approach allows virtually unlimited flexibility in accomplishing anything in an online experiment that a regular computer (or smartphone, etc.) is capable of. Apart from offering a fast introduction for complete beginners, this tutorial may also serve as a helpful guideline for more experienced programmers and researchers. Connected to the tutorial, a specific implementation is also given via the free and open-source template project at https://github.com/gasparl/expapp, intended to be improved by the community to always follow the latest technological advancements and general good practices.