What exactly is the benefit of the HTML5 async attribute on script elements?

Question

I have some confusion around the new async attribute to the script element in HTML5 that I hope someone can give a clear answer to.

Browsers are capable of Parallel Conn

Answer 1

setting async attribute to true makes sure that the script is loaded along with the rendering of html in parallel.This is essential because if script is placed at end of body and in html we are using something that depends on javascript code,so it won't be loaded and creates issue defer can be used but defer just pauses execution of script and renders html