在线运行代码 - 菜鸟教程

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(cainiaoplay.com)</title>
<script src="https://cdn.staticfile.org/jquery/1.10.2/jquery.min.js"></script>
</head>
<body>

<span></span>
<script>
$(function () { 
	var keys =$.map( [0, 1, 52, 97], function (a) {
		return (a > 50 ? a - 45 : null);
	});
	$("span").text(keys.join(", "));
})
</script>
 
</body>
</html>

源代码

动行结果