用法
<?
include("counter.php");
Counter(__FILE__);//为文件增加一个计数
if($PHP_SELF=="/index.php")
{
$count=Counter("INDEX_COUNT");//为首页增加一个计数
}
else
{
$count=Counter("INDEX_COUNT","",0);//取得首页计数
}
echo "你是第$count个访问者";
?>
--------counter.php-----------
<?
if(!isset($PHP_INCLUDE_COUNTER_PHP))
{$PHP_INCLUDE_COUNTER_PHP=__FILE;

$counter_error_state=0;
$counter_error_msg="";
function Counter($file,$query="",$add=1)
{
  $db_name="database";
  $db_user="username";
  $db_pass="password";
  $db_table="counter";

  if(empty($file))
  {
 $counter_error_state=-100;
 $counter_error_msg="缺少第一个参数或参数为空";
 return -100;
  }
  global $PHP_SELF,$QUERY_STRING,$counter_error_state,$counter_error_msg;
  if(empty($db_user)||!$db_user||$db_user=="")$res=@mysql_connect("localhost");
  else $res=@mysql_connect("localhost",$db_user,$db_pass);
  if(!$res)
  {
 $counter_error_states=-10;
 $counter_error_msg="不能连接数据库";
 return -10;
  }
  if(!@mysql_select_db($db_name))
  {
 $counter_error_states=-11;
 $counter_error_msg="不能选择数据库";
 return -11;
  }
  else
  {
 if(!$db_res=@mysql_query("SELECT * FROM ".$db_table))
 {
if(!$db_res=@mysql_query("CREATE TABLE ".$db_table." (id INTEGER AUTO_INCREMENT,PRIMARY KEY (id),file VARCHAR(255),query VARCHAR(255),time VARCHAR(255),count INT)"))
{
  $counter_error_states=-20;
  $counter_error_msg="不能创建数据表";
  return -20;
}
@mysql_free_result($db_res);
 }
 $str="SELECT * FROM ".$db_table." WHERE file=\"".$file."\" AND query=\"".$query."\"";

 if(!$db_res=@mysql_query($str))
 {
$counter_error_states=-30;
$counter_error_msg="不能查询记录";
return -30;
 }
 $num=@mysql_num_rows($db_res);
 if($num>1)
 {
$counter_error_states=-40;
$counter_error_msg="发生没有预期的错误=数据行数错误";
return -40;
 }
 $count=0;
 $str="INSERT ";
 $strWhere="";
 if($num==1)
 {
$row=@mysql_fetch_array($db_res);
@mysql_free_result($db_res);
$count=$row["count"];
$id=$row["id"];
$str="UPDATE ";
$strWhere=" WHERE id=$id";
 }
 if($add<1)return $count;
 $count+=$add;
 $str.=$db_table." SET file=\"".$file."\",query=\"".$query."\",time=\"".date("Y;n;d;G;i;s")."\",count=".$count.$strWhere;
 $db_res=@mysql_query($str);
 if(!$db_res)
 {
$counter_error_states=-50;
$counter_error_msg="不能添加或更新记录";
return -50;
 }
 return $count;
  }
}

}
?>