<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>不死神兔</title>
</head>
<body>
<input type="text" id="txt" />
<input type="button" id="btn" value="测试" onclick="get()"/>
</body>
</html>
function get(){
var x =Number(document.getElementById("txt").value);
alert(num(x));
}
function num(n){
if(n==1||n==2){
return 1;
}
return (num(n-1)+num(n-2)) ;
}