$(document).ready(function() {        var nScrollHight = 0; //滚动距离总长(注意不是滚动条的长度)        var nScrollTop = 0; //滚动到的当前位置        var nDivHight = $("#pdiv").height();        $("#pdiv").scroll(function() {            nScrollHight = $(this)[0].scrollHeight;            nScrollTop = $(this)[0].scrollTop;            if (nScrollTop + nDivHight >= nScrollHight)                $("#btsubmit").removeAttr("disabled");        });    });