JQuery+DIV自定义滚动条样式的具体实现

JQuery计算滚动条长度和位置，代码如下：

javascript

复制代码 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
    }