A continuing hurdle in the cognitive modeling of human- computer interaction is the difficulty with allowing models to interact with the same interfaces as the user. Multiple at- tempts have been made to add this functionality (e.g., Hope, Schoelles, & Gray, 2014) in limited domains. This paper presents a solution allowing models to interact with web browser-based software, while requiring little modification to the task code. Simplified Interfacing for Modeling Cognition - JavaScript (SIMCog-JS) allows the modeler to specify how elements in the interface are translated into ACT-R chunks, allows keyboard and mouse interaction with JavaScript code, and allows sending ACT-R commands from the external soft- ware (e.g., to add instructions). The benefits, drawbacks, and future functionality of SIMCog-JS are discussed.