This thesis describes spoofax2ace, the tool to generate source code editors which can run in the browser. The features which are common in state of the art desktop-computer based source code editors are investigated after which the difficulties in getting these features running on the Web are discussed. We present, implement, and compare multiple approaches in constructing a fully semantically aware source code editor which runs in the browser. The most useful aspects in these approaches arecombined in the proposition of our “editor-generator” which produces browser-based source code editors with as sole input a language declaration in the form of a Spoofaxproject.