MDN Web API
https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Client-side_web_APIs/Introduction
Web API collection
https://developer.mozilla.org/en-US/docs/Web/API
Security
https://www.thoughtco.com/what-javascript-cannot-do-2037666
Document
https://developer.mozilla.org/ko/docs/Web/API/Document
Window
https://developer.mozilla.org/en-US/docs/Web/API/Window
Viewport
https://developer.mozilla.org/en-US/docs/Glossary/layout_viewport
Navigator
https://developer.mozilla.org/en-US/docs/Web/API/Navigator
DOM (Document Object Model)
https://developer.mozilla.org/en-US/docs/Web/API/Document_Object_Model/Introduction
DOM API
https://developer.mozilla.org/en-US/docs/Web/API/HTML_DOM_API
Node
https://developer.mozilla.org/en-US/docs/Web/API/Node
Event Target
https://developer.mozilla.org/en-US/docs/Web/API/EventTarget
addEventListerner()는 EventTarget에서 지원해주는 API
(추가) removeEventListener(), dispatchEvent()
CSSOM (CSS Object Model)
https://developer.mozilla.org/en-US/docs/Web/API/CSS_Object_Model
