<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
</head>
<body>
<script>
//模板快捷键 ！+tab
//for循环的方法
function add() {
var sum = 0;
for (var i = 1; i <= 100; i++) {
sum += i;
}
return sum;
}
document.write(add());
document.write(" | 我是分割线 | ");
//递归方法
function addNum(n) {
if (n == 1) return 1;
return n + addNum(n - 1);
}
var result = addNum(100);
document.write(result);
</script>
</body>
</html>
原文：https://www.cnblogs.com/JennieLiu/p/14946293.html