<!DOCTYPE html>
<html lang="ko">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title></title>
<script>
let color = ["white", "yellow", "aqua", "purple"];
//document.write(color[0]);
let i = 0;
function changeColor(){
i++
if(i >= color.length){
i=0; //i의 값이 4가 되지 않도록 0으로 초기화 작업해준다.(if문이 없으면 undefinde)
}
let bodyTag = document.getElementById("theBody");
bodyTag.style.backgroundColor = color[i];
console.log("i : " + i);
console.log("color[i]" + color[i]);
}
</script>
</head>
<body id="theBody">
<button onclick="changeColor();">배경색 바꾸기</button>
</body>
</html>