Difference between querySelectorAll and getElementsByClassName

From Javascript, both the methods can be used to return multiple elements in the document but the difference is in what it returns.

• .querySelectorAll : Non-Live node list - Returns all the elements that matches the specified CSS selector(s) as a static NodeList object.
• .getElementsByClassName : Live node list - Returns all the elements that matches the spcified CSS class name as a HTMLCollection.

var elements1 = document.querySelectorAll(".clickable"); 
var elements2 = document.getElementsByClassName("clickable"); 

getElementsByClassName() is useful when working with dynamic elements as its updated when the DOM changes.