[JavaScript] Operation

최은서·2023년 11월 6일

자바스크립트(JavaScript)

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1. if

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<script type="text/javascript">
	var score = prompt('당신의 점수를 입력하세요','');
	var grade;
	
	if(score >= 90 && score <= 100){
		grade = 'A';
	}else if(score >= 80 && score < 90){
		grade = 'B';
	}else if(score >= 70 && score < 80){
		grade = 'C';
	}else if(score >= 60 && score < 70){
		grade = 'D';
	}else if(score >= 0 && score < 60){
		grade = 'F';
	}else{
		grade = '?';
	}
	
	document.write('점수 : ' + score + '<br>');
	document.write('등급 : ' + grade);
</script>
</body>
</html>

2. switch

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<script type="text/javascript">
	var score = prompt('당신의 점수를 입력하세요','');
	var grade;
	
	if(score < 0 || score > 100){
		document.write('잘못 입력했습니다.');
	}else{
		//Math.floor(숫자) : 소수점 자리 이하 절삭
		switch(Math.floor(score/10)){
		case 10 :
		case 9 : grade = 'A'; break;
		case 8 : grade = 'B'; break;
		case 7 : grade = 'C'; break;
		case 6 : grade = 'D'; break;
		default : grade = 'F';
		}
		
		document.write('점수 : ' + score + '<br>');
		document.write('등급 : ' + grade);
	}
</script>
</body>
</html>

3. for

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<script type="text/javascript">
	document.write('<table border="1">');
	
	for(var i=1;i<=9;i++){ //곱해질 수
		document.write('<tr>');
		for(var j=2;j<=9;j++){ //단
			document.write('<td>');
			document.write(j + ' * ' + i + ' = ' + j * i);
			document.write('</td>');
		}
		document.write('</tr>');
	}
	document.write('</table>');
</script>
</body>
</html>

4. while

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<script type="text/javascript">
	var i = 1; //초기값
	var sum = 0;
		  //조건식
	while(i <= 100){
		sum += i; //누적
		i++; //증감식
	}
	document.write('1부터 100까지의 합 : ' + sum);
</script>
</body>
</html>

5. doWhile

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<script type="text/javascript">
	var value = 0;
	
	while(value++ < 5){
		document.write(value + '번째 반복문<br>');
	}
	
	document.write('-------------<br>');
	
	value = 0;
	
	do{
		document.write(value + '번째 반복문<br>');
	}while(value++ < 5);
    
</script>
</body>
</html>

6. break

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<script type="text/javascript">
	for(var i=0;i<5;i++){
		for(var j = 0;j < 5;j++){
			if(j == 3){
				break; //break에 포함된 for문만 빠져나감	
			}
			document.write(i + ', ' + j + '<br>');
		}
	}
	
	document.write('----------------<br>');
	
	//break label문을 사용해서 원하는 반목문 빠져나가기
	outer_loop:
	for(var i = 0;i < 5;i++){
		for(var j = 0;j < 5;j++){
			if(j == 3){
				break outer_loop;
			}
			document.write(i + ', ' + j + '<br>');
		}
	}
</script>
</body>
</html>

7. continue

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<script type="text/javascript">
	for(var i=1;i<=10;i++){
		if(i % 2 == 1){
			//홀수이면 현재 반복을 중지하고 다음 반복을 수행
			//짝수만 출력됨
			continue;
		}
		document.write(i + '<br>');
	}
</script>
</body>
</html>

최은서

이전 포스트

[JavaScript] Operator

다음 포스트

[JavaScript] Operation

자바스크립트(JavaScript)

1. if

2. switch

3. for

4. while

5. doWhile

6. break

7. continue

[JavaScript] Operator

[JavaScript] Function_01

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