1-10的阶乘（封装练习）
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<script>
function jx(n){
var s=1;
for(var i=1;i<n;i++){
s*=i
}
return s;
}
alert(jx(10));
</script>
</body>
</html>
