A tiny, simple CommonJS require() implemetation in browser-side, only 30+ lines.

First put require.js on your page.

<script src="require.js" />

Then use require.register to register your module.

require.register("browser/debug.js", function(module, exports, require){
  // Module code goes here
});

Now you can use require function to load the module.

var debug = require("browser/debug.js");

MIT