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Home >Web Front-end >JS Tutorial >JS realizes the layer effect code that scrolls with the scroll bar on the web page_javascript skills

JS realizes the layer effect code that scrolls with the scroll bar on the web page_javascript skills

WBOY
WBOYOriginal
2016-05-16 15:33:531183browse

The example in this article describes the JS implementation of the layer effect code that scrolls with the scroll bar on the web page. Share it with everyone for your reference, the details are as follows:

The scrolling layer code on this webpage follows the scroll bar. Drag the scroll bar to see the effect. The code for the couplet advertisement is also based on this. The floating layer on the right can also be closed with a little processing. Implement the code for a floating ad, run it and see the effect first.

The screenshot of the running effect is as follows:

The online demo address is as follows:

http://demo.jb51.net/js/2015/js-web-fixed-scroll-adv-codes/

The specific code 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>随滚动条滚动的层</title>
<style>
body{ margin:0; padding:0; font-size:12px; font-family:"宋体",Arial, Helvetica, sans-serif;}
div,p,ul,ol,li,dl,dt,dd,h1,h2,h3,h4,h5,h6,form,input,form{ margin:0; padding:0;}
h1,h2,h3,h4,h5,h6{font-size:100%;font-weight:normal;}
img{ border:0;}
ol,ul{list-style:none;}
a{ text-decoration:none; color:#fff;}
a:hover{ text-decoration:none;}
#scroll_div{ width:100px; height:400px; background:#990; }
#btn_close,#btn_gotop{ cursor:pointer;}
</style>
</head>
<body>
<div style=" width:1002px;height:42px;margin:0 auto; background-color:#060;">头</div>
<div style="width:1002px; margin:0 auto; background-color:#f60;">
我们提供各类编程源码、<br>素材、书籍教程、设计模板、<br>网页特效代码以及常用软件下载等，<br>做有质量的<br>学习型源码下载站。
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</div>
<div style=" width:1002px;height:95px;margin:0 auto; background-color:#060;">底</div>
<div id="scroll_div">
<span id="btn_close">关闭</span><br />
<span id="btn_gotop">返回顶部</span>
</div>
<script type="text/javascript">
var Bianyuan = {
 //添加事件2(DOM-保证this指向对象是obj)
 addEvent : function(obj, type, fn){
  if (obj.attachEvent){
   obj['e'+type+fn] = fn;
   obj[type+fn] = function(){obj['e'+type+fn](window.event);}
   obj.attachEvent('on'+type, obj[type+fn]);
  }else{
   obj.addEventListener(type, fn, false);
  }
 },
 //获取id元素
 $ : function(id){
  return document.getElementById(id);
 },
 //取得浏览器可视区size
 getBrowserSize : function(){
  var pageWidth = window.innerWidth,
   pageHeight = window.innerHeight;
  if (typeof pageWidth != "number"){
   if (document.compatMode == "CSS1Compat"){
    pageWidth = document.documentElement.clientWidth;
    pageHeight = document.documentElement.clientHeight;
   } else{
    pageWidth = document.body.clientWidth;
    pageWidth = document.body.clientHeight;
   }
  }
  //ie减去17滚动条宽度
  if(!window.ActiveXObject){
   pageWidth -= 17;
  }
  return {
   width : pageWidth,
   height : pageHeight
  }
 },
 //获取滚动条高度
 getPageScroll : function(){ 
  var yScroll; 
  if (self.pageYOffset) { 
   yScroll = self.pageYOffset; 
  } else if (document.documentElement && document.documentElement.scrollTop){ 
   yScroll = document.documentElement.scrollTop; 
  } else if (document.body) { 
   yScroll = document.body.scrollTop; 
  } 
  return yScroll; 
 }
}
function scrollBar(scrollId, dir, headHeight, footHeight, areaWidth, o){
 //滚动框宽高
 var scrollBar = Bianyuan.$(scrollId),
  barWidth = scrollBar.offsetWidth,
  barHeight = scrollBar.offsetHeight;
 //可视区宽高
 var pageWidth = Bianyuan.getBrowserSize().width,
  pageHeight = Bianyuan.getBrowserSize().height;
 //内容宽高
 var widthMore = document.documentElement.scrollWidth,
  heightMore = document.body.scrollHeight||(document.documentElement.scrollHeight);  
 //最大宽高
 var maxWidth = Math.max(pageWidth, widthMore),
  maxHeight = Math.max(pageHeight, heightMore);
 scrollBar.style.position = 'absolute';
 //设置top--假设滚动框高度小于整个页面高度，如果大于直接将其隐藏
 if (maxHeight < (barHeight + footHeight + footHeight + 4)){
  scrollBar.style.display = 'none';
 }else{
  //不挡顶部---如果想改距顶高度，改下边的第一个2值
  scrollBar.style.top = Bianyuan.getPageScroll() + headHeight + 2 + 'px';
  //不挡底部
  if ((heightMore - Bianyuan.getPageScroll() - barHeight) <= footHeight){
   scrollBar.style.top = heightMore - footHeight - barHeight - 2 + 'px';
  }
 }
 //无视主体内容-左右
 if (dir == 'left' && areaWidth == 1){
  scrollBar.style.left = 2 + 'px';
 }else if (dir == 'right' && areaWidth == 1){
  scrollBar.style.left = maxWidth - barWidth - 2 + 'px';
 //根据主体内容宽-左右
 }else if (dir == 'left' && areaWidth != 1){
  if (pageWidth >= (barWidth*2 + areaWidth + 4)){
   scrollBar.style.left = (pageWidth - areaWidth)/2 - barWidth - 2 + 'px';
  }else{
   scrollBar.style.left = 2 + 'px';
  }
 }else if (dir == 'right' && areaWidth != 1){
  if (pageWidth >= (barWidth*2 + areaWidth + 4)){
   scrollBar.style.left = (pageWidth - areaWidth)/2 + areaWidth + 2 + 'px';
  }else{
   scrollBar.style.left = maxWidth - barWidth - 2 + 'px';
  }
 }
 //关闭和返回顶部
 if (o){
  if (o.btnClose){
   var closeBtn = Bianyuan.$(o.btnClose);
   Bianyuan.addEvent(closeBtn, 'click', function(){
    scrollBar.style.display = 'none';
   })
  }
  if (o.goTop){
   var gotopBtn = Bianyuan.$(o.goTop);
   Bianyuan.addEvent(gotopBtn, 'click', function(){
    document.documentElement.scrollTop = 0;
    document.body.scrollTop = 0;
   })
  }
 }
 //改变窗口大小或滚动条滚动
 resizeWindow(scrollId, dir, headHeight, footHeight, areaWidth, o);
}
function resizeWindow(scrollId, dir, headHeight, footHeight, areaWidth, o){
 window.onresize = function(){scrollBar(scrollId, dir, headHeight, footHeight, areaWidth, o);}
 window.onscroll = function(){scrollBar(scrollId, dir, headHeight, footHeight, areaWidth, o);}
}
</script>
<script type="text/javascript">
scrollBar("scroll_div", "right", 42, 95, 1002, {btnClose:"btn_close",goTop:"btn_gotop"});
</script>
</body>
</html>

I hope this article will be helpful to everyone in JavaScript programming.

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