return b-a;//这里写成b-a,与-1，有什么区别吗?

<script type="text/javascript">

   function sortNum(a,b) {

     return b-a;//这里写成b-a,与-1，有什么区别吗?

   }

var myarr = new Array("80","16","50","6","100","1");

document.write(myarr.sort(sortNum));