<!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>
var num = prompt('请输入第几项')
function fn(n){
if (n == 1 || n == 2){
return 1;
}
return fn(n-2)+ fn(n-1);
}
document.write(fn(num));
</script>
</body>
</html>
`var fn = function sum(num1,num2){
return num1+num2;
}
var result = fn(12,5);
document.write(result);
var fn = function sum(num1,num2){
return num1-num2;
}
var result = fn(12,5);
document.write(result);
var fn = function sum(num1,num2){
return num1/num2;
}
var result = fn(12,5);
document.write(result);
var fn = function sum(num1,num2){
return num1*num2;
}
var result = fn(12,5);
document.write(result);
`
