<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta http-equiv="X-UA-Compatible" content="ie=edge" />
<title>数组去重</title>
</head>
<body>
<script>
var arr1 = [10, 20, 30, 30, 20, "s", "s"];
var arr2 = []; // 新数组，把不重复的元素放进新数组
for (var i = 0; i < arr1.length; i++) {
var e = arr1[i];
if (arr2.indexOf(e) < 0) {
// 判断e这个元素在arr2这个新数组是否存在，小于0，证明e元素不存在arr2，所以把e放进新数组里面，大于0的就不用放进新数组里面
arr2.push(e);
}
}
console.log(arr2);
// 只用一个数组
</script>
</body>
</html>