js implements up and down scrolling effect with buttons_javascript skills-JS Tutorial-php.cn

js implements up and down scrolling effect with buttons_javascript skills

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Release： 2016-05-16 15:59:32

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The example in this article describes the js implementation of the up and down scrolling effect with buttons. Share it with everyone for your reference. The specific implementation method is as follows:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>js带按钮上下滚动效果</title>
<style type="text/css">
ul{
 margin:0;
 padding:0;
 list-style:none;
 height:100000px;
}
li{
 margin:0;
 padding:0;
 width:100px;
 height:100px;
 display:block;
 float:top;
 margin-bottom:5px;
 background:#009900;
}
#img_bag{
 width:110px;
 height:600px;
 background:#F2F2F2;
 margin:0 auto;
 text-align:center;
}
#img_bag #img{
 width:100px;
 height:525px;
 background:#969696;
 overflow:hidden;
 margin:auto;
}
</style>
</head>
<body>
<div id="img_bag">
 <a href="javascript:void(0)" onmousedown="moveTop()">
 <img src="upp.jpg" border="0" /></a>
 <div id="img">
 <ul>
  <li>1</li>
  <li>2</li>
  <li>3</li>
  <li>4</li>
  <li>5</li>
  <li>6</li>
  <li>7</li>
  <li>8</li>
  <li>9</li>
  <li>10</li>
  <li>11</li>
  <li>12</li>
 </ul>
 </div>
 <a href="javascript:void(0)" onmousedown="moveBottom()">
 <img src="down.jpg" border="0" /></a>
</div>
<script type="text/javascript">
function $(obj){
 //获取指定对象
 return document.getElementById(obj);
}
var maxHeight=$("img").getElementsByTagName("ul")[0].getElementsByTagName("li").length*105;
//滚动图片的最大高度
var targety = 211;
//一次滚动距离
var dx;
var a=null;
function moveTop(){
 var le=parseInt($("img").scrollTop);
 if(le>211){
 targety=parseInt($("img").scrollTop)-211;
 }else{
 targety=parseInt($("img").scrollTop)-le-1;
 }
 scTop();
}
function scTop(){
 dx=parseInt($("img").scrollTop)-targety;
 $("img").scrollTop-=dx*.3;
 clearScroll=setTimeout(scTop,50);
 if(dx*.3<1){
 clearTimeout(clearScroll);
 }
}
function moveBottom(){
 var le=parseInt($("img").scrollTop)+211;
 var maxL=maxHeight-600;
 if(le<maxL){
 targety=parseInt($("img").scrollTop)+211;
 }else{
 targety=maxL
 }
 scBottom();
}
function scBottom(){
 dx=targety-parseInt($("img").scrollTop);
 $("img").scrollTop+=dx*.3;
 a=setTimeout(scBottom,50);
 if(dx*.3<1){
 clearTimeout(a)
 }
}
</script>
</body>
</html>

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The operation effect is as follows:

I hope this article will be helpful to everyone’s JavaScript programming design.