<div id="demo">
<div class="saylist">
<a href="#"><img src="images/0.jpg" width="50" height="50" alt="demo" /></a>
<div class="saytxt">
<p><strong><a href="http://www.jb51.net">Shuro</a></strong><span>
8分钟前</span> 说：</p>
<div class="say">评论内容。。。</div>
</div>
</div>
...
</div>

#demo{width:400px; height:80px; margin:80px auto; border-bottom:1px dotted #d3d3d3}
.saylist{margin:8px auto; height:80px; padding:4px 0;}
.saylist img{float:left; width:50px; margin:4px}
.saytxt{float:right; width:320px; overflow:hidden}
.saytxt p{line-height:18px}
.saytxt p strong{margin-right:6px}
.saytxt p span{color:#999}
.say{margin-top:3px; font-size:14px; font-weight:bold}

function formatSay($say,$dt,$uid){
$say=htmlspecialchars(stripslashes($say));
return'
<div class="saylist"><a href="#"><img src="images/'.$uid.'.jpg" width="50"
height="50" alt="demo" /></a>
<div class="saytxt">
<p><strong><a href="#">demo_'.$uid.'</a></strong> <span>'.tranTime($dt).'</span> 说：
</p><div class="say">'.$say.'</div>
</div>
<div class="clear"></div>
</div>';
}

function tranTime($stime) {
$rtime = date("m-d H:i",$stime);
$htime = date("H:i",$stime);
$day_time = date("j",$stime);
$today=date("j",time());
$ds = $today - $day_time;
$time = time() - $stime;
if ($time < 60) {
$str = '刚刚';
}
elseif ($time < 60 * 60) {
$min = floor($time/60);
$str = $min.'分钟前';
}
elseif ($time < 60 * 60 * 24) {
$h = floor($time/(60*60));
$str = $h.'小时前 '.$htime;
if($ds==1)
$str = '昨天 '.$rtime;
}
elseif ($time < 60 * 60 * 24 * 2) {
$str = '昨天 '.$rtime;
if($ds==2)
$str = '前天 '.$rtime;
}elseif($time < 60 * 60 * 24 * 3){
$str = '前天 '.$rtime;
if($ds>2)
$str = $rtime;
}
else {
$str = $rtime;
}
return $str;
}

require_once('connect.php'); //连接数据库文件
require_once('function.php'); //函数文件
$query=mysql_query("select * from say order by id desc limit 0,15");
while ($row=mysql_fetch_array($query)) {
$sayList.=formatSay($row[content],$row[addtime],$row[userid]);
}

<div id="demo">
<?php echo $sayList;?>
</div>

$(function(){
//除了显示第一个saylist,其他的都隐藏
$(".saylist").hide().eq(0).show();
//自循环函数，循环展示信息
(function showNextSay(){
//每条信息展示7.5秒
$(".saylist:visible").delay(7500).fadeOut("slow",function(){
$(this).appendTo("#demo");
//展示下一条
$(".saylist:first").fadeIn("slow",function(){
//再次调用函数
showNextSay();
});
});
})();
});