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jQuery实现判断滚动条到底部

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jQuery,判断滚动条到底部

判断滚动条到底部,需要用到DOM的三个属性值,即scrollTop、clientHeight、scrollHeight。

scrollTop为滚动条在Y轴上的滚动距离。

clientHeight为内容可视区域的高度。

scrollHeight为内容可视区域的高度加上溢出(滚动)的距离。

从这个三个属性的介绍就可以看出来,滚动条到底部的条件即为scrollTop + clientHeight == scrollHeight。

废话不多少说,赶紧上代码(兼容不同的浏览器)。

lazyload.js

//滚动条在Y轴上的滚动距离  function getScrollTop(){  var scrollTop = 0, bodyScrollTop = 0, documentScrollTop = 0;  if(document.body){    bodyScrollTop = document.body.scrollTop;  }  if(document.documentElement){    documentScrollTop = document.documentElement.scrollTop;  }  scrollTop = (bodyScrollTop - documentScrollTop > 0) ? bodyScrollTop : documentScrollTop;  return scrollTop;}  //文档的总高度  function getScrollHeight(){  var scrollHeight = 0, bodyScrollHeight = 0, documentScrollHeight = 0;  if(document.body){    bodyScrollHeight = document.body.scrollHeight;  }  if(document.documentElement){    documentScrollHeight = document.documentElement.scrollHeight;  }  scrollHeight = (bodyScrollHeight - documentScrollHeight > 0) ? bodyScrollHeight : documentScrollHeight;  return scrollHeight;}  //浏览器视口的高度  function getWindowHeight(){  var windowHeight = 0;  if(document.compatMode == "CSS1Compat"){    windowHeight = document.documentElement.clientHeight;  }else{    windowHeight = document.body.clientHeight;  }  return windowHeight;}  window.onscroll = function(){  if(getScrollTop() + getWindowHeight() == getScrollHeight()){    alert("you are in the bottom!");  }};

lazyload-jQuery.js

$(window).scroll(function(){  var scrollTop = $(this).scrollTop();  var scrollHeight = $(document).height();  var windowHeight = $(this).height();  if(scrollTop + windowHeight == scrollHeight){    alert("you are in the bottom");  }});

lazyLoad.html

<!doctype html><html lang="en" style="height:900px;"> <head> <meta charset="UTF-8"> <meta name="Author" content="forever"> <link rel="stylesheet" href="css/lazyload.css" /> <script type="text/javascript" src="js/jquery-1.7.2.min.js"></script> <title>lazyLoad</title> <script type="text/javascript">     $(function(){    var $ul=$("#lazyLoadWrap").find("ul");    $(window).scroll(function(){        var scrollTop = $(this).scrollTop();        var scrollHeight = $(document).height();        var windowHeight = $(this).height();       if(scrollTop + windowHeight == scrollHeight){          for(var i=0;i<6;i++){            $ul.append("<li>Hello</li>");          }       }    });  }); </script> </head> <body>  <div id="lazyLoadWrap">    <ul>      <li></li>      <li></li>      <li></li>      <li></li>      <li></li>      <li></li>      <li></li>      <li></li>      <li></li>      <li></li>      <li></li>      <li>12</li>    </ul>  </div> </body></html>

以上所述就是本文的全部内容了,希望大家能够喜欢。


jQuery,判断滚动条到底部  
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