用js做的返回顶部

来源:互联网 发布:javzoo2016最新域名 编辑:程序博客网 时间:2024/05/17 07:09

<!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>

    <script language="javascript" type="text/javascript">
function goTopEx(){
        var obj=document.getElementById("goTopBtn");
        function getScrollTop(){
                return document.documentElement.scrollTop;
            }
        function setScrollTop(value){
                document.documentElement.scrollTop=value;
            }   
        window.onscroll=function(){getScrollTop()>0?obj.style.display="":obj.style.display="none";}
        obj.onclick=function(){
            var goTop=setInterval(scrollMove,10);
            function scrollMove(){
                    setScrollTop(getScrollTop()/1.1);
                    if(getScrollTop()<1)clearInterval(goTop);
                }
        }
    }

    </script>
    <style type="text/css">
        BODY
        {
        <!--演示效果实际用的时候可以去掉-->
            height: 3600px;
        }

        #goTopBtn
        {
            position: fixed;
            text-align: center;
            line-height: 30px;
            width: 30px;
            bottom: 35px;
            height: 33px;
            font-size: 12px;
            cursor: pointer;
            right: 0px;
            _position: absolute;
            _right: auto;
        }
    </style>
    <title></title>
</head>
<body style="text-align: center">
    <div style="display: none" id="goTopBtn">
        <img border="0" src="images/lanren_top.jpg"></div>

    <script type="text/javascript">goTopEx();</script>
    <p>
        超出首屏范围,即会出现TOP按钮,否则自动隐藏。<br />
    </p>
</body>
</html>

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