Yes, GeoGebra works with Javascripting since it actively supports and depends on it to work properly. To summarize, GeoGebra supports applets (things you create), XML codes that you can apply to the HTML code, HTML for export and Javascript objects. However, the documentation regarding Javascript is rather large, therefore, I recommend checking the Wiki page where everything about applets, objects, HTML, and XML is explained.
Wiki page: https://wiki.geogebra.org/en/Reference:JavaScript#GeoGebra.27s_XML_format
Note: Take advantage of the available examples to learn how to implement Javascript in GeoGebra.
