简单思路：用DIV和DIV自身的滚动条相互控制内容的滚动，DIV自身的滚动条样式可以用DIV层覆盖，重写滚动条样式
JQuery计算滚动条长度和位置，代码如下：

<script type="text/javascript">var scrMinHeight = 1; //滚动条最小高度var scrMaxHeight = 0; //滚动条最大高度var scrDefualtTop = 80; //滚动条默认位置var scrHeight = 0;//初始化滚动条function InitScroll() {scrMaxHeight = $("#mainScrollContent").height(); //文本框高度scrHeight = document.getElementById("mainScrollContent").scrollHeight; //滚动文本高度scrHeight = parseInt((scrMaxHeight / scrHeight) * scrMaxHeight);if (scrHeight <= scrMinHeight) { scrHeight = scrMinHeight; }if (scrHeight >= scrMaxHeight) { $("#scrollContent").hide(); }else {$("#scrollContent").show();$("#scrollContent .tiao_mid").css("height", (scrHeight - 19) + "px");}}$(document).ready(function () {$(".bod").height(($(document).height() - 80) + "px");$("#mainScrollContent").height(($(document).height() - 125) + "px");scrMaxHeight = ($(document).height() - 125); //滚动条最大高度$("#scrollBody").height(($(document).height() - 125) + "px");$("#scrollBodyBack").height(($(document).height() - 125) + "px");InitScroll();$("#mainScrollContent").scroll(function () {ChangeScroll();});var y1 = 0;$("#scrollContent").mousedown(function (event) {var scrContentTop = $("#scrollContent").css("top");y1 = event.clientY - parseInt(scrContentTop.replace("px", ""));$("#scrollContent").mousemove(function (event) {if ((event.clientY - y1) < scrDefualtTop) {$("#scrollContent").css("top", scrDefualtTop + "px");}else if ((event.clientY - y1) > (scrDefualtTop + scrMaxHeight - scrHeight)) {$("#scrollContent").css("top", (scrDefualtTop + scrMaxHeight - scrHeight) + "px");}else {$("#scrollContent").css("top", (event.clientY - y1) + "px");}ChangeScrollContent();});}).mouseup(function () {$("#scrollContent").unbind("mousemove");}).mouseout(function () {$("#scrollContent").unbind("mousemove");});});//改变滚动内容位置function ChangeScrollContent() {var scrTop = $("#scrollContent").css("top");var st = parseInt(scrTop.replace("px", ""));st = ((st - scrDefualtTop) * document.getElementById("mainScrollContent").scrollHeight) / scrMaxHeight$("#mainScrollContent").scrollTop(st); //滚动的高度}//改变滚动条位置function ChangeScroll() {var scrTop = $("#mainScrollContent").scrollTop(); //滚动的高度scrTop = (scrTop * scrMaxHeight) / document.getElementById("mainScrollContent").scrollHeight + scrDefualtTop;$("#scrollContent").css("top", scrTop + "px");}</script>

滚动区域内容DIV：

<div class="jtc_neir" id="Div1" style="height: 100px;">营业总收入:11.66亿元(同比增长-1.75%)<br /><a href="bank.aspx">dddd</a>净利润:0.19亿元(同比增长23.72%)<br />每股收益:0.04元<br />净资产收益率:1.58%<br />毛利率:12.22%(同比增长39.89%)<br />总资产:30.46亿元(同比增长-7.14%)<br />as大苏打撒旦撒<br />阿斯蒂芬多个地方营业总收入:11.66亿元(同比增长-1.75%)<br />净利润:0.19亿元(同比增长23.72%)<br />每股收益:0.04元<br />净资产收益率:1.58%<br />毛利率:12.22%(同比增长39.89%)<br />总资产:30.46亿元(同比增长-7.14%)<br />as大苏打撒旦撒<br />阿斯蒂芬多个地方营业总收入:11.66亿元(同比增长-1.75%)<br />净利润:0.19亿元(同比增长23.72%)<br />每股收益:0.04元<br />净资产收益率:1.58%<br />毛利率:12.22%(同比增长39.89%)<br />总资产:30.46亿元(同比增长-7.14%)<br />as大苏打撒旦撒<br />阿斯蒂芬多个地方营业总收入:11.66亿元(同比增长-1.75%)<br />净利润:0.19亿元(同比增长23.72%)<br />每股收益:0.04元<br />净资产收益率:1.58%<br />毛利率:12.22%(同比增长39.89%)<br />总资产:30.46亿元(同比增长-7.14%)<br />as大苏打撒旦撒<br />阿斯蒂芬多个地方营业总收入:11.66亿元(同比增长-1.75%)<br />净利润:0.19亿元(同比增长23.72%)<br />每股收益:0.04元<br />净资产收益率:1.58%<br />毛利率:12.22%(同比增长39.89%)<br />总资产:30.46亿元(同比增长-7.14%)<br />as大苏打撒旦撒<br />阿斯蒂芬多个地方</div>
<div class="jtc_tiao" style="background-color: rgb(196,206,208); z-index: 2;" id="Div2">
</div>
<div class="jtc_tiao" style="background-color: rgb(222,222,222); z-index: 1; width: 16px;"id="Div3">
</div>
<div class="jtc_tiao" id="Div4"><div class="tiao_up"></div><div class="tiao_mid"></div><div class="tiao_bottom"></div>
</div>

主要样式：

.jtc_neir{margin-left:20px; margin-right:20px; color:#000000; font-size:12px; background:none; line-height:32px; overflow-y:scroll;overflow-x:hidden;scrollbar-3dlight-color:rgb(222,222,222);scrollbar-arrow-color:rgb(222,222,222);scrollbar-base-color:rgb(222,222,222);scrollbar-darkshadow-color:rgb(222,222,222);scrollbar-face-color:rgb(222,222,222);scrollbar-highlight-color:rgb(222,222,222);scrollbar-shadow-color:rgb(222,222,222);}.jtc_tiao{width:8px; position:absolute; top:80px; right:20px; z-index:10;}
.tiao_up{width:8px; height:10px; background:url(../images/scrollbar-3.jpg) left top no-repeat; line-height:0px; overflow:hidden;}
.tiao_mid{width:8px; background:url(../images/scrollbar-3.jpg) -39px center  repeat-y; line-height:0px; overflow:hidden;}
.tiao_bottom{width:8px; height:10px; background:url(../images/scrollbar-3.jpg) -13px bottom no-repeat;font-size:0; line-height:0px; overflow:hidden;}