The “require” function is only available in the “https://stackoverflow.com/questions/28696511/bundle.js” script context. Browserify will take all the script files necessary and put them into the “https://stackoverflow.com/questions/28696511/bundle.js” file, so you should only have to include “https://stackoverflow.com/questions/28696511/bundle.js” in the HTML file, not the “script.js” file.