案例
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<title></title>
<link rel="stylesheet" href="">
</head>
<body>
</body>
</html>
<script>
function outFn(a) {
return function (b) {
console.log(a+b);
}
}
var fn1 = outFn(5);
fn1(6);//11
</script>