return문은 함수에서 결괏값을 반환할 때 사용합니다.
function func4(){
let str = "함수가 실행되었습니다.";
return str;
}
let value = func4();
document.write(value);function func6(){
document.write("함수가 출력되었습니다.6");
return;
document.write("함수가 출력되었습니다.7");
}
func6();
//함수가 출력되었습니다.6function func5(num1,num2){
return num1 + num2;
}
let result = func5(100,200);
document.write(result);
//300Last updated
let arr1 = [100,200,300,400,500];
let sum2 = 0;
for(let i = 0; i<arr1.length; i++){
sum2 += arr1[i];
}
let avg2 = sum2 / arr1.length;
document.write(avg2);function testAvg(arrData){
let sum = 0;
for(let i = 0; i<arrData.length; i++){
sum += Number(prompt(arrData[i]+"점수는?","0"));
}
let avg = sum / arrData.length;
return avg;
}
let arrSubject = ["국어","수학","영어","과학"];
let result = testAvg(arrSubject);
document.write(result);<!DOCTYPE html>
<html lang="ko">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<div id="galleryZone"></div>
<p><img id="photo" src="img/pic_1.jpg" alt="이미지1" style="width: 500px;"></p>
<div>
<button onclick="gallery(0)">이전</button>
<button onclick="gallery(1)">다음</button>
</div>
<script>
let num = 1;
function gallery(direct){
if(direct){
if(num == 8){
return;
}
num++;
} else{
if(num == 1){
return;
}
num--;
}
console.log(num);
let imgTag = document.getElementById("photo");
imgTag.setAttribute("src","img/pic_"+num+".jpg");
}
</script>
</body>
</html><div id = "galley">
<img id="img" src="img/pic_1.jpg" alt = "이미지1" style = "width: 300px;">
<button class = "prev">이전이미지</button>
<button class = "next">다음이미지</button>
</div>
<script>
document.getElementById("img").setAttribute("alt","야경 이미지입니다.");
//버튼을 클릭하면 경고창 출력
let prev = document.querySelector(".prev");
let next = document.querySelector(".next");
let image = document.getElementById("img");
let num = 1;
prev.addEventListener("click", function(){
if( num ==1 ){
alert("처음이미지입니다.")
return;
}
num--;
image.setAttribute("src","img/pic_" + num + ".jpg");
console.log(num);
});
next.addEventListener("click", function(){
if( num == 8 ){
alert("마지막 이미지입니다.")
return;
}
num++;
image.setAttribute("src","img/pic_"+num+".jpg");
console.log(num);
});