toUpperCase() / toLowerCase () / trim() 에 대하여....!!!

toUpperCase() / toLowerCase

toUpperCase는 문자열을 대문자로 변경하고, toLowerCase는 문자열을 소문자로 변경

번호	기본값	메서드	리턴값
1	javascript	toUpperCase()	JAVASCRIPT
2	javascript	toLowerCase()	JAVASCRIPT

const str1 = "javascript";
const currentStr1 = str1.toUpperCase();
    
document.querySelector(".sample02_N1").innerHTML="1";
document.querySelector(".sample02_Q1").innerHTML="javascript";
document.querySelector(".sample02_M1").innerHTML="toUpperCase()";
document.querySelector(".sample02_P1").innerHTML=currentStr1;
                
const str2 = "JAVASCRIPT";
const currentStr2 = str1.toUpperCase();
    
document.querySelector(".sample02_N2").innerHTML="2";
document.querySelector(".sample02_Q2").innerHTML="JAVASCRIPT";
document.querySelector(".sample02_M2").innerHTML="toLowerCase()";
document.querySelector(".sample02_P2").innerHTML=currentStr2;

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trim() : 문자 / trimStart() / trimEnd() :

문자열의 공백을 제거해주는 메서드 입니다.

번호	기본값	메서드	리턴값
1	javascript	trim()	javascript
2	javascript	trimStart()	javascript
3	javascript	trimEnd()	javascript

const str1 = "         javascript         ";
const currentStr1 = str1.trim();

document.querySelector(".sample03_N1").innerHTML="1";
document.querySelector(".sample03_Q1").innerHTML=str1;
document.querySelector(".sample03_M1").innerHTML="trim()";
document.querySelector(".sample03_P1").innerHTML=currentStr1;

const str2 = "         javascript         ";
const currentStr2 = str2.trimStart();

document.querySelector(".sample03_N2").innerHTML="2";
document.querySelector(".sample03_Q2").innerHTML=str2;
document.querySelector(".sample03_M2").innerHTML="trimStart()";
document.querySelector(".sample03_P2").innerHTML=currentStr2;

const str3 = "         javascript         ";
const currentStr3 = str3.trimEnd();

document.querySelector(".sample03_N3").innerHTML="3";
document.querySelector(".sample03_Q3").innerHTML=str3;
document.querySelector(".sample03_M3").innerHTML="trimEnd()"
document.querySelector(".sample03_P3").innerHTML=currentStr3;