回到顶部

<!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" xml:lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html;charset=UTF-8"/>
    <title>回到顶部 - 豪情</title>
    <style type="text/css">
        *{ margin:0; padding:0;}
        body{font:12px/1.125 Arial,Helvetica,sans-serif;background:#fff;}
        a:focus,input,textarea{outline-style:none;}
        a{color:#0a8cd2;text-decoration:none;}
        a:hover{text-decoration:underline;}
        .none{display:none}
        .demo{ height:2000px;}
        .gotop{ 18px;line-height:1.2;padding:7px 0px 7px 2px;background-color:#000;color:#fff;font-size:12px;text-align:center;position:fixed;_position:absolute;right:0px;bottom:100px;_bottom:"auto";cursor:pointer;opacity:0.6;filter:Alpha(opacity=60);border-radius:5px 0 0 5px; display:none;}
        .gotop:hover{ text-decoration:none;opacity:0.7;filter:Alpha(opacity=70);}
    </style>
</head>
<body>
<div class="demo"></div>
<script type="text/javascript">
    (function(){
        function viewSize(){
            var doc = document,
                    de = doc.documentElement;
            return {
                'width': (window.innerWidth || (de && de.clientWidth) || doc.body.clientWidth),
                'height': (window.innerHeight || (de && de.clientHeight) || doc.body.clientHeight)
            };
        }
        function getScrollTop(){
            return document.documentElement.scrollTop || document.body.scrollTop;
        }
        var btn = null,
            timer = 0;
        function apendScroll(){
            btn = document.createElement('a');
            btn.href = 'javascript:void(0)';
            btn.className = 'gotop';
            btn.innerHTML = '回到顶部';
            document.body.appendChild(btn);
        }
        apendScroll();
        function ie6Top(){
            if(!window.XMLHttpRequest){
                btn.style.top = getScrollTop() + viewSize().height - 200 + 'px';
            }
        }
        window.onscroll = function(){
            btn.style.display = getScrollTop() > 0 ? 'block' : 'none';
            ie6Top();
        }
        btn.onclick = function(){
            timer = setInterval(function(){
                var scrollTop = getScrollTop();
                var iSpeed = Math.floor(- scrollTop / 8);
                if(scrollTop == 0){
                    clearInterval(timer);
                }
                ie6Top();
                document.documentElement.scrollTop = document.body.scrollTop = scrollTop + iSpeed;
            }, 30);
        }
    }());
</script>
</body>
</html>