How to integrate Node.js into a PHP Website?

I find PHP way easier to understand and generally use than Node.js, however there's some parts of a website that are "impossible" to make with only PHP, such as realtime chat, realtime notifications, etc.

I was wondering how I could possibly integrate Node.js(& socket.io) in a website (PHP), meaning that the forms, inputs, etc... would be processed and stored using PHP & MySQL, but at the same time use Node.js to process the already stored Username / Message and rendering them realtime.

There's already some answers here on StackOverflow however I couldn't seem to get any of them working.

via Sidexx