ie8 最底部

 <script language="JavaScript" type="text/javascript">
            function test() {
                var topHeight = document.getElementById("Top").scrollHeight;
                var infoHeight = document.getElementById("Info").scrollHeight;
                var endHeight = document.getElementById("End").scrollHeight;
                var allHeight = document.documentElement.clientHeight;

                var bottom = document.getElementById("End");
                if ((topHeight + infoHeight + endHeight) < allHeight) {
                    bottom.style.position = "absolute";
                    bottom.style.bottom = "0";
                } else {
                    bottom.style.position = "";
                    bottom.style.bottom = "";
                }

                setTimeout(function() { test(); }, 10);
            }
            test();
        </script>