不明白升降序是什么原理，这么改一下也可以，为什么？
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Array对象 </title>
<script type="text/javascript">
function sortNum(b,a) {
return a-b;
}
var myarr = new Array("80","16","50","6","100","1");
document.write(myarr.sort(sortNum));
</script>
</head>
<body>
</body>
</html>
结果是100,80,50,16,6,1，为什么会这样
