[vhakulinen]

Thats just one data point, and for which you could argue that javascript has not one, but two null values: null and undefined.

PHP got (or is getting?) type hinting, while javascript doesn't have such thing (typescript or flow doesn't count). Javascript is event loop based, while PHP is (afaik) request->response based. These days, javascript usually is compiled for web, while PHP just sits there on the server and you can swap out the source files when you upgrade. You could go on and on.