<script type="text/javascript">
 function sortNum(a,b) {
 return a - b;
//升序，如降序，把“a - b”该成“b - a”
}
var myarr = new Array("80","16","50","6","100","1");
 document.write(myarr + "<br>");
 document.write(myarr.sort(sortNum));
</script>

运行结果：

80,16,50,6,100,1
1,6,16,50,80,100

不理解这个函数怎么实现升序的