title: Parser blocking vs render blocking
body: <p>I've been reading Google Developers documentation on optimizing web performance. I'm a little confused with the terminology used there. Both CSS and JavaScript files block DOM construction. But, CSS is called render-blocking whereas JavaScript is called parser-blocking. What is the difference in the 'parser-blocking' and 'render-blocking' terms? Or are they the same and the terminology is just interchangeably used? </p>