实现斐波那契数列的前20项的打印，1 1 2 3 5 8 ........
<!DOCTYPE html>
<html lang="zh_CN">
<head>
<meta charset="UTF-8">
<title>作业2</title>
</head>
<body>
<script>
function f(x) {
if (x == 1) {
return 1;
} else if (x == 2) {
return 2;
} else {
return f(x - 1) + f(x - 2);
}
}
for (let i = 1; i < 20; i++) {
console.log(f(i))
}
</script>
</body>
</html>
