jQuery implements back to top function-JS Tutorial-php.cn

jQuery implements back to top function

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Release： 2018-04-19 15:18:15

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This time I will bring you jQuery to implement the return to the top function. What are the precautions for jQuery to implement the return to the top function. The following is a practical case, let’s take a look.

<!DOCTYPE html>
<html>
 <head>
  <meta charset="UTF-8">
  <title>回到顶部</title>
  <style type="text/css">
   body{
    width: 100%;
    height: 10000px;
   }
   #totop{
    width: 50px;
    height: 50px;
    line-height: 50px;
    background: magenta;
    font-size: 20px;
    position: fixed;
    right: 50px;
    bottom: 50px;
   }
  </style>
 </head>
 <body>
 </body>
 <script src="js/jquery-1.8.3.min.js" ></script>
 <script>
  //写在common.js文件中用来调用即可
  //1获取滚动条当前的位置
  function getScrollTop() {
   var scrollTop = 0;
   if (document.documentElement && document.documentElement.scrollTop) {
    scrollTop = document.documentElement.scrollTop;
   } else if (document.body) {
    scrollTop = document.body.scrollTop;
   }
   return scrollTop;
  };
  //2获取文档完整的高度
  function getScrollHeight() {
   return Math.max(document.body.scrollHeight, document.documentElement.scrollHeight);
  };
  //3回到顶部
  function toTop(n) {
   $(window).on('scroll', function() {
    //console.log(getScrollTop()+"!"+getScrollHeight());
    if ($("#totop").size() > 0) {
     if (getScrollTop() < $(window).height() * n) {
      $("#totop").remove();
     }
    } else {
     if (getScrollTop() >= $(window).height() * n) {
      $("body").after("<p id=&#39;totop&#39;>totop</p>");
      //插入了新标签 ，记得添加样式！
      $("#totop").on('click', function() {
       scroll(0,200);
      });
     }
    }
   });
  };
  //xxx.js文件来执行
  $(function(){
   toTop(2);
  })
 </script>
</html>

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I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!