为什么b能输出，而b.reverse()不能输出
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Array对象 </title>
<script type="text/javascript">
var myarr1= ["我","爱","你"];
var t = myarr1.join("");
// document.write(t.reverse());
var b = t.concat("哟");
document.write(b);
document.write(b.reverse());
</script>
</head>
<body>
</body>
</html>
