<html lang="ja">
<head>
<meta charset="UTF-8">
<title>html練習</title>
</head>
<body>
<img src="omikuzi.png">
<input id="omikuzi" type="button" value="おみくじを引く">
<script>
document.getElementById("omikuzi").onclick = function(){
let rnd = Math.floor(Math.random() * 6);
switch(rnd){
case 0:
omikuzi="？？？";
break;
case 1:
omikuzi="大吉";
break;
case 2:
omikuzi="凶";
break;
case 3:
omikuzi="大凶";
break;
case 4:
omikuzi="大大凶";
break;
case 5:
omikuzi="大大大凶";
break;
dafault:
omikuzi="？？？";
break;
}
alert(omikuzi);
}
</script>
</body>
</html>