HTML, XML문서의 프로그래밍 interface
http://www.tcpschool.com/javascript/js_dom_concept#:~:text=%EB%AC%B8%EC%84%9C%20%EA%B0%9D%EC%B2%B4%20%EB%AA%A8%EB%8D%B8(DOM%2C%20Document,%ED%95%98%EA%B8%B0%20%EC%9C%84%ED%95%9C%20%EC%9D%BC%EC%A2%85%EC%9D%98%20%EC%9D%B8%ED%84%B0%ED%8E%98%EC%9D%B4%EC%8A%A4%EC%9E%85%EB%8B%88%EB%8B%A4.&text=%2D%20%EC%9E%90%EB%B0%94%EC%8A%A4%ED%81%AC%EB%A6%BD%ED%8A%B8%EB%8A%94%20%EC%A1%B4%EC%9E%AC%ED%95%98%EB%8A%94,%EC%9A%94%EC%86%8C%EB%A5%BC%20%EB%B3%80%EA%B2%BD%ED%95%A0%20%EC%88%98%20%EC%9E%88%EC%8A%B5%EB%8B%88%EB%8B%A4.
https://developer.mozilla.org/ko/docs/Web/API/Document_Object_Model/Introduction
