JQuery+DIV 사용자 정의 스크롤 바 스타일 구현

<script type="text/javascript">
    var scrMinHeight = 1; //       
    var scrMaxHeight = 0; //       
    var scrDefualtTop = 80; //       
    var scrHeight = 0;
    //      
    function InitScroll() {
        scrMaxHeight = $("#mainScrollContent").height(); //     
        scrHeight = document.getElementById("mainScrollContent").scrollHeight; //      
        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); //       
        $("#scrollBody").height(($(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");
        });
    });
    //        
    function ChangeScrollContent() {
        var scrTop = $("#scrollContent").css("top");
        var st = parseInt(scrTop.replace("px", ""));
        st = ((st - scrDefualtTop) * document.getElementById("mainScrollContent").scrollHeight) / scrMaxHeight
        $("#mainScrollContent").scrollTop(st); //     
    }
    //       
    function ChangeScroll() {
        var scrTop = $("#mainScrollContent").scrollTop(); //     
        scrTop = (scrTop * scrMaxHeight) / document.getElementById("mainScrollContent").scrollHeight + scrDefualtTop;
        $("#scrollContent").css("top", scrTop + "px");
    }
    </script>

<div class="jtc_neir" id="Div1" style="height: 100px;">
         :11.66  (    -1.75%)
    <br />
    <a href="bank.aspx">dddd</a>   :0.19  (    23.72%)
    <br />
        :0.04 
    <br />
          :1.58%
    <br />
       :12.22%(    39.89%)
    <br />
       :30.46  (    -7.14%)<br />
    as      
    <br />
                 :11.66  (    -1.75%)
    <br />
       :0.19  (    23.72%)
    <br />
        :0.04 
    <br />
          :1.58%
    <br />
       :12.22%(    39.89%)
    <br />
       :30.46  (    -7.14%)<br />
    as      
    <br />
                 :11.66  (    -1.75%)
    <br />
       :0.19  (    23.72%)
    <br />
        :0.04 
    <br />
          :1.58%
    <br />
       :12.22%(    39.89%)
    <br />
       :30.46  (    -7.14%)<br />
    as      
    <br />
                 :11.66  (    -1.75%)
    <br />
       :0.19  (    23.72%)
    <br />
        :0.04 
    <br />
          :1.58%
    <br />
       :12.22%(    39.89%)
    <br />
       :30.46  (    -7.14%)<br />
    as      
    <br />
                 :11.66  (    -1.75%)
    <br />
       :0.19  (    23.72%)
    <br />
        :0.04 
    <br />
          :1.58%
    <br />
       :12.22%(    39.89%)
    <br />
       :30.46  (    -7.14%)<br />
    as      
    <br />
            </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>

.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;}