What is Join() in jQuery?

Question

What is Join() in jquery? for example:

var newText = $(\"p\").text().split(\" \").join(\" \"); 

Answer 1

The practical use of this construct? It is a javascript replaceAll() on strings.

var s = 'stackoverflow_is_cool';  
s = s.split('_').join(' ');  
console.log(s);

will output:

stackoverflow is cool