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<!DOCTYPE HTML>
<html>
<head>
<title>自定义滚动条</title>
<meta charset="UTF-8">
<link rel="stylesheet" href="reset.css" type="text/css" />
<script type="text/javascript" src="js/jquery-1.11.2.min.js"> </script>
<script type="text/javascript">
(function($){
$.zUI = $.zUI || {}
$.zUI.emptyFn = function(){};
$.zUI.asWidget = [];
/*
* core代码，定义增加一个插件的骨架
*/
$.zUI.addWidget = function(sName,oSefDef){
//设置规范中的常量sFlagName、sEventName、sOptsName
$.zUI.asWidget.push(sName);
var w = $.zUI[sName] = $.zUI[sName] || {};
var sPrefix = "zUI" + sName
w.sFlagName = sPrefix;
w.sEventName = sPrefix + "Event";
w.sOptsName = sPrefix + "Opts";
w.__creator = $.zUI.emptyFn;
w.__destroyer = $.zUI.emptyFn;
$.extend(w,oSefDef);
w.fn = function(ele,opts){
var jqEle = $(ele);
jqEle.data(w.sOptsName,$.extend({},w.defaults,opts));
//如果该元素已经执行过了该插件，直接返回，仅相当于修改了配置参数
if(jqEle.data(w.sFlagName)){
return;
}
jqEle.data(w.sFlagName,true);
w.__creator(ele);
jqEle.on(jqEle.data(w.sEventName));
};
w.unfn = function(ele){
w.__destroyer(ele);
var jqEle = $(ele);//移除监听事件
if(jqEle.data(w.sFlagName)){
jqEle.off(jqEle.data(w.sEventName));
jqEle.data(w.sFlagName,false);
}
}
}
/*
* draggable
* 参数：obj{
* bOffsetParentBoundary:是否以定位父亲元素为边界,
* oBoundary:指定元素left和top的边界值，形如{iMinLeft:...,iMaxLeft:...,iMinTop:...,iMaxTop:...},与上一个参数互斥
* fnComputePosition:扩展函数，返回形如{left:...,top:...}的对象
* }
* 支持的自定义事件:
* "draggable.start":drag起始，就是鼠标down后触发
* "draggable.move":drag过程中多次触发
* "draggable.stop":drag结束触发，就是鼠标up后触发
*/
//注册draggable组件
$.zUI.addWidget("draggable",{
defaults:{
bOffsetParentBoundary:false,//是否以定位父亲元素为边界
oBoundary:null,//边界
fnComputePosition:null//计算位置的函数
},
__creator:function(ele){
var jqEle = $(ele);
jqEle.data($.zUI.draggable.sEventName,{
mousedown:function(ev){
var jqThis = $(this);
var opts = jqThis.data($.zUI.draggable.sOptsName);
jqThis.trigger("draggable.start");
var iOffsetX = ev.pageX - this.offsetLeft;
var iOffsetY = ev.pageY - this.offsetTop;
function fnMouseMove (ev) {
var oPos = {};
if(opts.fnComputePosition){
oPos = opts.fnComputePosition(ev,iOffsetX,iOffsetY);
}else{
oPos.iLeft = ev.pageX - iOffsetX;
oPos.iTop = ev.pageY - iOffsetY;
}
var oBoundary = opts.oBoundary;
if(opts.bOffsetParentBoundary){//如果以offsetParent作为边界
var eParent = jqThis.offsetParent()[0];
oBoundary = {};
oBoundary.iMinLeft = 0;
oBoundary.iMinTop = 0;
oBoundary.iMaxLeft = eParent.clientWidth - jqThis.outerWidth();
oBoundary.iMaxTop = eParent.clientHeight - jqThis.outerHeight();
}
if(oBoundary){//如果存在oBoundary，将oBoundary作为边界
oPos.iLeft = oPos.iLeft < oBoundary.iMinLeft ? oBoundary.iMinLeft : oPos.iLeft;
oPos.iLeft = oPos.iLeft > oBoundary.iMaxLeft ? oBoundary.iMaxLeft : oPos.iLeft;
oPos.iTop = oPos.iTop < oBoundary.iMinTop ? oBoundary.iMinTop : oPos.iTop;
oPos.iTop = oPos.iTop > oBoundary.iMaxTop ? oBoundary.iMaxTop : oPos.iTop;
}
jqThis.css({left:oPos.iLeft,top:oPos.iTop});
ev.preventDefault();
jqThis.trigger("draggable.move");
}
var oEvent = {
mousemove:fnMouseMove,
mouseup:function(){
$(document).off(oEvent);
jqThis.trigger("draggable.stop");
}
};
$(document).on(oEvent);
}});
}
});
/*
* panel
* 参数：obj{
* iWheelStep:鼠标滑轮滚动时步进长度
* sBoxClassName:滚动框的样式
* sBarClassName:滚动条的样式
* }
*/
$.zUI.addWidget("panel",{
defaults : {
iWheelStep:16,
sBoxClassName:"zUIpanelScrollBox",
sBarClassName:"zUIpanelScrollBar"
},
__creator:function(ele){
var jqThis = $(ele);
//如果是static定位，加上relative定位
if(jqThis.css("position") === "static"){
jqThis.css("position","relative");
}
jqThis.css("overflow","hidden");
//必须有一个唯一的直接子元素,给直接子元素加上绝对定位
var jqChild = jqThis.children(":first");
if(jqChild.length){
jqChild.css({top:0,position:"absolute"});
}else{
return;
}
var opts = jqThis.data($.zUI.panel.sOptsName);
//创建滚动框
var jqScrollBox = $("<div style=‘position:absolute;display:none;line-height:0;‘></div>");
jqScrollBox.addClass(opts.sBoxClassName);
//创建滚动条
var jqScrollBar= $("<div style=‘position:absolute;display:none;line-height:0;‘></div>");
jqScrollBar.addClass(opts.sBarClassName);
jqScrollBox.appendTo(jqThis);
jqScrollBar.appendTo(jqThis);
opts.iTop = parseInt(jqScrollBox.css("top"));
opts.iWidth = jqScrollBar.width();
opts.iRight = parseInt(jqScrollBox.css("right"));
//添加拖拽触发自定义函数
jqScrollBar.on("draggable.move",function(){
var opts = jqThis.data($.zUI.panel.sOptsName);
fnScrollContent(jqScrollBox,jqScrollBar,jqThis,jqChild,opts.iTop,0);
});
//事件对象
var oEvent ={
mouseenter:function(){
fnFreshScroll();
jqScrollBox.css("display","block");
jqScrollBar.css("display","block");
},
mouseleave:function(){
jqScrollBox.css("display","none");
jqScrollBar.css("display","none");
}
};
var sMouseWheel = "mousewheel";
if(!("onmousewheel" in document)){
sMouseWheel = "DOMMouseScroll";
}
oEvent[sMouseWheel] = function(ev){
var opts = jqThis.data($.zUI.panel.sOptsName);
var iWheelDelta = 1;
ev.preventDefault();//阻止默认事件
ev = ev.originalEvent;//获取原生的event
if(ev.wheelDelta){
iWheelDelta = ev.wheelDelta/120;
}else{
iWheelDelta = -ev.detail/3;
}
var iMinTop = jqThis.innerHeight() - jqChild.outerHeight();
//外面比里面高，不需要响应滚动
if(iMinTop>0){
jqChild.css("top",0);
return;
}
var iTop = parseInt(jqChild.css("top"));
var iTop = iTop + opts.iWheelStep*iWheelDelta;
iTop = iTop > 0 ? 0 : iTop;
iTop = iTop < iMinTop ? iMinTop : iTop;
jqChild.css("top",iTop);
fnScrollContent(jqThis,jqChild,jqScrollBox,jqScrollBar,0,opts.iTop);
}
//记录添加事件
jqThis.data($.zUI.panel.sEventName,oEvent);
//跟随滚动函数
function fnScrollContent(jqWrapper,jqContent,jqFollowWrapper,jqFlollowContent,iOffset1,iOffset2){
var opts = jqThis.data($.zUI.panel.sOptsName);
var rate = (parseInt(jqContent.css("top"))-iOffset1)/(jqContent.outerHeight()-jqWrapper.innerHeight())//卷起的比率
var iTop = (jqFlollowContent.outerHeight()-jqFollowWrapper.innerHeight())*rate + iOffset2;
jqFlollowContent.css("top",iTop);
}
//刷新滚动条
function fnFreshScroll(){
var opts = jqThis.data($.zUI.panel.sOptsName);
var iScrollBoxHeight = jqThis.innerHeight()-2*opts.iTop;
var iRate = jqThis.innerHeight()/jqChild.outerHeight();
var iScrollBarHeight = iScrollBarHeight = Math.round(iRate*iScrollBoxHeight);
//如果比率大于等于1，不需要滚动条,自然也不需要添加拖拽事件
if(iRate >= 1){
jqScrollBox.css("height",0);
jqScrollBar.css("height",0);
return;
}
jqScrollBox.css("height",iScrollBoxHeight);
jqScrollBar.css("height",iScrollBarHeight);
//计算拖拽边界，添加拖拽事件
var oBoundary = {iMinTop:opts.iTop};
oBoundary.iMaxTop = iScrollBoxHeight - Math.round(iRate*iScrollBoxHeight)+opts.iTop;
oBoundary.iMinLeft = jqThis.innerWidth() - opts.iWidth - opts.iRight;
oBoundary.iMaxLeft = oBoundary.iMinLeft;
fnScrollContent(jqThis,jqChild,jqScrollBox,jqScrollBar,0,opts.iTop);
jqScrollBar.draggable({oBoundary:oBoundary});
}
},
__destroyer:function(ele){
var jqEle = $(ele);
if(jqEle.data($.zUI.panel.sFlagName)){
var opts = jqEle.data($.zUI.panel.sOptsName);
jqEle.children("."+opts.sBoxClassName).remove();
jqEle.children("."+opts.sBarClassName).remove();
}
}
});
$.each($.zUI.asWidget,function(i,widget){
unWidget = "un"+widget;
var w = {};
w[widget] = function(args){
this.each(function(){
$.zUI[widget].fn(this,args);
});
return this;
};
w[unWidget] = function(){
this.each(function(){
$.zUI[widget].unfn(this);
});
return this;
}
$.fn.extend(w);
});
})(jQuery);
</script>
<style type="text/css">
#demo{
width:1000px;
height:500px;
border:10px solid gray;
margin:20px auto;
overflow:hidden;
position:relative;
}
.box{
height:500px;
width:1000px;
}
.zUIpanelScrollBox,.zUIpanelScrollBar{
width:10px;
top:4px;
right:2px;
border-radius:5px;
}
.zUIpanelScrollBox{
background:black;opacity:0.1;
filter:alpha(opacity=10);
}
.zUIpanelScrollBar{
background:#fff;opacity:0.8;
filter:alpha(opacity=80);
}
</style>
<script>
$(function(){
$("#demo").panel({iWheelStep:32});
});
</script>
</head>
<body>
<div id="demo">
<div>
<div class="box" style="background:green"></div>
<div class="box" style="background:pink"></div>
<div class="box" style="background:yellow"></div>
<div class="box" style="background:gray"></div>
<div class="box" style="background:blue"></div>
</div>
</div>
</body>
</html>
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原文地址：http://www.cnblogs.com/ricesm/p/5046399.html
