本文例項為大家分享了js實現自定義滾動條的具體程式碼，供大家參考，具體內容如下

1.HTML檔案

div1是滾動條，div2是滾動小球，div3是文字區域容器，div4是文字區域。

<div id="div">
 <div id="div1">
 <div id="div2"> </div>
 </div>
 <div id="div3">
 <div id="div4">
 <p>CSS3 教程</p>
 <p>CSS3 教程</p>
 <p>CSS3 簡介</p>
 <p>CSS3 邊框</p>
 <p>CSS3 圓角</p>
 <p>CSS3 背景</p>
 <p>CSS3 漸變</p>
 <p>CSS3 文字效果</p>
 <p>CSS3 字型</p>
 <p>CSS3 2D 轉換</p>
 <p>CSS3 3D 轉換</p>
 <p>CSS3 過渡</p>
 <p>CSS3 動畫</p>
 <p>CSS3 多列</p>
 <p>CSS3 使用者介面</p>
 <p>CSS3 圖片</p>
 <p>CSS3 按鈕</p>
 <p>CSS3 分頁</p>
 <p>CSS3 框大小</p>
 <p>CSS3 彈性盒子</p>
 <p>CSS3 多媒體查詢</p>
 <p>CSS3 多媒體查詢例項</p>
 </div>
 </div>
</div>

2.css樣式檔案

通過容器溢位隱藏，文字區域的絕對定位，然後再交給js處理。

*{padding: 0; margin: 0;}
#div{top:200px;left:25%;width: 50%;height: 300px; position: absolute; 
}
#div1{width: 20px; height: 300px; position: relative; 
background: #CCCCCC; border-radius: 28px; float: right; cursor: pointer;}
#div1 #div2{left: -4px;width: 28px;height: 28px;border-radius: 50%; background: red;
position: absolute;}

#div3{width: 90%; height: 300px; border: 2px solid #CCCCCC;
position: relative; float: left; overflow: hidden;}
#div3 #div4{top:0;left:0;width: 100%; position: absolute; font-family: "微軟雅黑";
font-size: 19px; letter-spacing: 1px; padding: 3px 6px;}

3.js指令碼程式碼

window.onload =function(){
 var allDiv =document.getElementById('div');
 var oDiv =document.getElementById('div2');
 var aDiv =document.getElementById('div1');
 var textDiv1 =document.getElementById('div3');
 var textDiv2 =document.getElementById('div4');
 
 // 進度條拖動，內容跟著運動事件
 oDiv.onmousedown =function(ev){
 var oEvent =ev||event;
 
 var disY =oEvent.clientY -oDiv.offsetTop;
 
 if(oDiv.setCapture){
 oDiv.onmousemove =mouseMove;
 oDiv.onmouseup =mouseUp;
 
 oDiv.setCapture();
 }else{
 document.onmousemove =mouseMove;
 document.onmouseup =mouseUp;
 }
 
 function mouseMove(ev){
 var oEvent =ev||event; 
 var t =oEvent.clientY -disY; 
 var bottomLine = aDiv.offsetHeight-oDiv.offsetHeight; 
 
 
 if(t <0){
 t =0;
 }else if(t >bottomLine){
 t =bottomLine;
 }
 
  var percent =t/272;
  
 oDiv.style.top =t+'px';
 textDiv2.style.top =-(textDiv2.offsetHeight-textDiv1.offsetHeight)*percent+'px';
 
 };
 
 function mouseUp(){
 this.onmousemove =null;
 this.onmouseup =null;
 
 if(oDiv.releaseCapture){
 oDiv.releaseCapture();
 }
 };
 
 return false;
 };
 
 // 點選進度條，開啟定時器，小球做勻速運動到達後，清楚定時器
 aDiv.onmousedown=function(ev){
 var oEvent =ev||event; 
 var divY =oEvent.clientY-allDiv.offsetTop;
 var timer =null;var speed=10;
 
 
 clearInterval(timer)
 timer = setInterval(function(){
 var percent=oDiv.offsetTop/272;
 
 
 if(oDiv.offsetTop<divY-28){
 oDiv.style.top =oDiv.offsetTop + speed +'px';
 textDiv2.style.top =-(textDiv2.offsetHeight-textDiv1.offsetHeight)*percent +'px';
 }else if(oDiv.offsetTop>divY){
 oDiv.style.top =oDiv.offsetTop - speed +'px';
 textDiv2.style.top =-(textDiv2.offsetHeight-textDiv1.offsetHeight)*percent +'px';
 }else if(oDiv.offsetTop>260){
 oDiv.offsetTop = 272+'px';
 clearInterval(timer);
 }else if(oDiv.offsetTop<10){
 oDiv.offsetTop = 0+'px';
 clearInterval(timer);
 }else{
 clearInterval(timer);
 }
 
 
 },10);
 
 }
 
}

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支援我們。