PHP统计当前在线用户数实例讲解

<div class="demo">   <div id="total">当前在线：<span id="onlinenum"></span></div>   <ul id="onlinelist">     <li><img src="loader.gif"></li>   </ul> </div> 

.demo{width:150px; margin:20px auto; font-size:14px} #total{padding:6px 10px; background:#090 url(arr.png) no-repeat right top; color:#fff; cursor:pointer; -moz-border-radius:5px; -webkit-border-radius:5px; border-radius:5px; -moz-box-shadow:0 0 3px #ccc; -webkit-box-shadow:0 0 3px #ccc;box-shadow:0 0 3px #ccc;} #onlinelist{background:#f7f7f7; border:1px solid #d3d3d3; display:none; -moz-border-radius:5px; -webkit-border-radius:5px; border-radius:5px; -moz-box-shadow:0 0 3px #ccc; -webkit-box-shadow:0 0 3px #ccc;box-shadow:0 0 3px #ccc;} #onlinelist li{height:20px; line-height:20px;padding:4px 6px;border-bottom:1px dotted #d9d9d9} #onlinelist li span{float:right} #onlinelist li:hover{background:#fff} 

CREATE TABLE IF NOT EXISTS `online` (  `id` int(11) NOT NULL AUTO_INCREMENT,  `ip` varchar(30) NOT NULL,  `province` varchar(64) NOT NULL,  `addtime` int(10) NOT NULL DEFAULT '0',  PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8; 

include_once('connect.php'); //连接数据库  $ip = get_client_ip(); //获取客户端IP $time = time(); //查询表中是否有ip为当前访客IP的记录 $query = mysql_query("select id from online where ip='$ip'"); if(!mysql_num_rows($query)){//如果不存在访客IP   if($_COOKIE['geoData']){//如果存在cookie，则获取用户的区域     $province = $_COOKIE['geoData']; //区域（省份）   }else{     $api = "http://int.dpool.sina.com.cn/iplookup/iplookup.php?format=json&ip=$ip";     $json = file_get_contents($api);//    $arr = json_decode($json,true);//解析json     $province = $arr['province'];//获取省份     setcookie('geoData',$province,$time+600); //设置cookie，设置过期时间为10分钟   }   //将访客信息插入到数据表中   mysql_query("insert into online (ip,province,addtime) values ('$ip','$province','$time')"); }else{//如果存在，则更新该用户访问时间   mysql_query("update online set addtime='$time' where ip='$ip'"); } //删除已过期的记录 $outtime = $time-600; mysql_query("delete from online where addtime<$outtime"); //统计总记录数，即在线用户数 list($totalOnline) = mysql_fetch_array(mysql_query("select count(*) from online")); echo $totalOnline;//输出在线总数 mysql_close(); 

function get_client_ip() {   if (getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown"))     $ip = getenv("HTTP_CLIENT_IP");   else if (getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown"))     $ip = getenv("HTTP_X_FORWARDED_FOR");   else if (getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown"))     $ip = getenv("REMOTE_ADDR");   else if (isset ($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown"))     $ip = $_SERVER['REMOTE_ADDR'];   else     $ip = "unknown";   return ($ip); } 

include_once('connect.php');//连接数据库 //查询区域统计 $sql = "select province,count(*) as total from online group by province order by total desc"; $result = mysql_query($sql); while($row=mysql_fetch_array($result)){   $list[] = array(     'province' => $row['province'],     'total' => $row['total']   );  } echo json_encode($list);//以json格式输出 

$(function(){   $("#onlinenum").load("online.php");      $(".demo").hover(function(){     $("#onlinelist").slideDown("fast");     var str = '';     $.getJSON("geo.php",function(json){       $.each(json,function(index,array){         str = str + "<li><span>"+array['total']+"</span>"+array['province']+"</li>";       });       $("#onlinelist").html(str);     });   },function(){     $("#onlinelist").slideUp("fast");   }); });