div模拟滚动条

  1 <!doctype html>
  2 <html>
  3 <head>
  4 <meta charset="utf-8">
  5 <title>scrolling</title>
  6 </head>
  7 <style>
  8 *{ margin: 0; padding: 0;}
  9 p{ line-height: 50px;}
 10 p:nth-child(2n){ background: #ffeaea;}
 11 p:nth-child(2n+1){ background: #cceaea;}
 12 
 13 .box{ margin-top:100px; position: relative; width:400px; height:200px; border: 1px solid #000; overflow: hidden;}
 14 .scroll-content{ position: absolute; left: 0; top: 0; width: 100%;}
 15 
 16 .scroll-bg{ display: none; width: 7px; height: 100%; border-left: 1px solid #e1e1e1; border-right: none; border-top: none; border-bottom: none; background-color: #f2f2f2; position: absolute; _zoom: 1; top: 0; right: 0; cursor: pointer;}
 17 .scroll-bg:hover{ border-color:#bfbfbf; background-color:#a1a1a1}
 18 .scroll-bar{z-index: 20; position: absolute; width: 7px; height: 15px; background-color: #f00; overflow: hidden;left: 0px; cursor: pointer;}
 19 </style>
 20 <body>
 21  
 22 <div class="box" id="box">
 23     <div class="scroll-content">
 24         <p>1</p>
 25         <p>2</p>
 26         <p>3</p>
 27     </div>
 28     <div class="scroll-bg">
 29         <div class="scroll-bar"></div>
 30     </div>
 31 </div>
 32 
 33 
 34 <div class="box" id="box1">
 35     <div class="scroll-content">
 36         <p>1</p>
 37         <p>2</p>
 38         <p>3</p>
 39         <p>4</p>
 40         <p>5</p>
 41         <p>6</p>
 42         <p>7</p>
 43         <p>8</p>
 44         <p>9</p>
 45         <p>10</p>
 46     </div>
 47     <div class="scroll-bg">
 48         <div class="scroll-bar"></div>
 49     </div>
 50 </div>
 51 
 52 <div class="box" id="box2" style="height: 300px;">
 53     <div class="scroll-content">
 54         <p>1</p>
 55         <p>2</p>
 56         <p>3</p>
 57         <p>4</p>
 58         <p>5</p>
 59         <p>6</p>
 60         <p>7</p>
 61         <p>8</p>
 62         <p>9</p>
 63         <p>10</p>
 64     </div>
 65     <div class="scroll-bg">
 66         <div class="scroll-bar"></div>
 67     </div>
 68 </div>
 69  
 70 <script src="jquery-1.8.3.min.js"></script>
 71 <script>
 72 //jquery mousewheel插件
 73 (function ($) {
 74     var types = ['DOMMouseScroll', 'mousewheel'];
 75     $.event.special.mousewheel = {
 76         setup: function () {
 77             if (this.addEventListener) {
 78                 for (var i = types.length; i;) {
 79                     this.addEventListener(types[--i], handler, false);
 80                 }
 81             } else {
 82                 this.onmousewheel = handler;
 83             }
 84         },
 85         teardown: function () {
 86             if (this.removeEventListener) {
 87                 for (var i = types.length; i;) {
 88                     this.removeEventListener(types[--i], handler, false);
 89                 }
 90             } else {
 91                 this.onmousewheel = null;
 92             }
 93         }
 94     };
 95     $.fn.extend({
 96         mousewheel: function (fn) {
 97             return fn ? this.bind("mousewheel", fn) : this.trigger("mousewheel");
 98         },
 99         unmousewheel: function (fn) {
100             return this.unbind("mousewheel", fn);
101         }
102     });
103     function handler(event) {
104         var orgEvent = event || window.event, args = [].slice.call(arguments, 1), delta = 0, returnValue = true, deltaX = 0, deltaY = 0;
105         event = $.event.fix(orgEvent);
106         event.type = "mousewheel";
107         // Old school scrollwheel delta
108         if (event.originalEvent.wheelDelta) { delta = event.originalEvent.wheelDelta / 120; }
109         if (event.originalEvent.detail) { delta = -event.originalEvent.detail / 3; }
110         // New school multidimensional scroll (touchpads) deltas
111         deltaY = delta;
112         // Gecko
113         if (orgEvent.axis !== undefined && orgEvent.axis === orgEvent.HORIZONTAL_AXIS) {
114             deltaY = 0;
115             deltaX = -1 * delta;
116         }
117         // Webkit
118         if (orgEvent.wheelDeltaY !== undefined) { deltaY = orgEvent.wheelDeltaY / 120; }
119         if (orgEvent.wheelDeltaX !== undefined) { deltaX = -1 * orgEvent.wheelDeltaX / 120; }
120         // Add event and delta to the front of the arguments
121         args.unshift(event, delta, deltaX, deltaY);
122         return $.event.handle.apply(this, args);
123     }
124 })(jQuery);
125 
126 
127 
128 
129 //自己封装一个scrolling插件
130 (function($){
131     $.scrolling = function(obj){
132         var $scrollContent = obj.find(".scroll-content"),
133             $scrollBg = obj.find(".scroll-bg"),
134             $scrollBar = obj.find(".scroll-bar"),
135              clientH = obj.height(), //可见区域高度
136             winH = $scrollContent.height(), //滚动区域高度
137             atH = Math.floor(clientH * .75), //每次滚动为可见区域3/4
138             num = Math.ceil(winH/atH)-1, ///可以滚动的次数
139             pos = 0, //当前区域值
140             barH = Math.floor(clientH/num), ///bar高度
141             barAtH = Math.floor((clientH-barH)/(num-1)), ///滚动条每次滚动高度
142         
143             maxH = clientH - barAtH, //滚动条y最大值
144             barContentH = (winH-clientH)/maxH; ///滚动条对应右侧滚动长度
145             
146         $scrollBar.height(barH);//设置滚动条高度
147         
148         //判断是否显示滚动条
149         if(winH <= clientH){
150             return false;    
151         }else{
152             $scrollBg.show();
153         }
154         
155         //鼠标滚轮
156         obj.bind('mousewheel', function(e,deta) { 
157             if(deta < 0){ //向上滚动
158                 if(pos>num-2)return false;
159                 pos++;
160             }else{ //向上滚动
161                 if(pos<1)return false;
162                 pos--;
163             }
164             
165             $scrollContent.stop(true,false).animate({"top":-pos*atH}, 300);
166             $scrollBar.stop(true,false).animate({"top":pos*barAtH}, 300);
167             
168             return false;
169         });  
170         
171         //滚动条、内容区域滚动
172         var changeScroll = function (y){
173             $scrollBar.css({'top':y+"px"});
174             $scrollContent.css({'top':-y*barContentH+"px"},100);
175         }
176         
177         //滚动条拖拽
178         obj.find(".scroll-bar").mousedown(function(e){
179             var position = $(this).position();
180             var y = e.pageY - position.top;
181             
182             $(document).bind("mousemove",function(ev){
183                 $(this).bind('selectstart',function(){return false;});
184                 var _y = ev.pageY - y;
185                 if(_y <= 0 || _y >= maxH)return false;
186                 console.log(_y)
187                 changeScroll(_y)
188             });
189             
190         });
191  
192         $(document).mouseup(function(){
193             $(this).unbind("mousemove");
194         });
195         
196         //阻止点击父级往上冒泡
197         $scrollBar.click(function (){
198              return false;    
199         })
200         
201         //点击滚动条父级
202         $scrollBg.click(function (e){
203             var y = (e.pageY-$(this).offset().top-barH/2);
204             if(y < 0){
205                 y = 0;    
206             }else if(y > maxH){
207                 y = maxH;        
208             }
209             changeScroll(y)
210         })
211        
212     };
213 })(jQuery)
214 
215 //调用
216 $.scrolling($("#box"))
217 $.scrolling($("#box1"))
218 $.scrolling($("#box2"))
219 </script>
220 </body>
221 </html>

p.s:简易版本还需要完善(1.滚动条往下滚动整除有余数,滚到最后没有处理,2.鼠标滚轮最后一屏下面可能有旁白没有处理)

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原文地址:https://www.cnblogs.com/make/p/4414898.html