[자바스크립트] 유효성 검사(날짜,전화번호)

0912를 09/12로 변환

let number = "2020".replace(/(\d{2})(\d{2})/, '$1/$2');

\d{2} - 숫자 두자리 표현

결과 09/12

전화번호 하이픈 추가

let cellPhone = "01012345678".replace(/(01[016789])([1-9]{1}[0-9]{2,3})([0-9]{4})$/,"$1-$2-$3")

결과 010-1234-5678