PHP实现的浏览器检查类

<?php
//原作者：epsilon7
//sonymusic([email]sonymusic@163.net[/email])
class browserdetector {
 var $ua = "";  //$http_user_agent的内容
 var $browser= "unknown";  //浏览器类型
 var $platform  = "unknown";  //操作系统
 var $version= "";  //浏览器版本号
 var $majorver  = "";  //浏览器主版本号
 var $minorver  = "";  //浏览器副版本号
 /* 构造函数开始 */
 function browserdetector(){
  $this->ua  = getenv(http_user_agent);
  $preparens = "";
  $parens = "";
  $i = strpos($this->ua,"(");
  if ($i >= 0)  {
    $preparens = trim(substr($this->ua,0,$i));
    $parens = substr($this->ua,$i+1,strlen($this->ua));
    $j = strpos($parens,")");
    if($j>=0) {
     $parens = substr($parens,0,$j);
    }
  }
  else  {
    $preparens = $this->ua;
  }
  $browver = $preparens;
  $token = trim(strtok($parens,";"));
  while($token)  {
    if($token=="compatible") {
    }
    elseif(preg_match("/msie/i","$token")) {
     $browver = $token;
    }
    elseif(preg_match("/opera/i","$token")) {
     $browver = $token;
    }
    elseif(preg_match("/x11/i","$token") || preg_match("/sunos/i","$token") || preg_match ("/linux/i","$token")) {
     $this->platform  = "unix";
    }
    elseif(preg_match("/win/i","$token")) {
     $this->platform  = $token;
    }
    elseif(preg_match("/mac/i","$token") || preg_match("/ppc/i","$token")) {
     $this->platform  = $token;
    }
    $token = strtok(";");
  }
  $msieindex = strpos($browver,"msie");
  if($msieindex >= 0)  {
    $browver = substr($browver,$msieindex,strlen($browver));
  }
  $leftover  = "";
  if(substr($browver,0,strlen("mozilla")) == "mozilla")  {
    $this->browser = "netscape";
    $leftover=substr($browver,strlen("mozilla")+1,strlen($browver));
  }
  elseif(substr($browver,0,strlen("lynx")) == "lynx")  {
    $this->browser = "lynx";
    $leftover=substr($browver,strlen("lynx")+1,strlen($browver));
  }
  elseif(substr($browver,0,strlen("msie")) == "msie") {
    $this->browser = "ie";
    $leftover=substr($browver,strlen("msie")+1,strlen($browver));
  }
  elseif(substr($browver,0,strlen("microsoft internet explorer")) == "microsoft internet explorer")  {
    $this->browser = "ie";
    $leftover=substr($browver,strlen("microsoft internet explorer")+1,strlen($browver));
  }
  elseif(substr($browver,0,strlen("opera")) == "opera")  {
    $this->browser = "opera";
    $leftover=substr($browver,strlen("opera")+1,strlen($browver));
  }
  $leftover = trim($leftover);
  $i=strpos($leftover," ");
  if($i > 0)  {
    $this->version = substr($leftover,0,$i);
  }
  else  {
    $this->version = $leftover;
  }
  $j = strpos($this->version,".");
  if($j >= 0)  {
    $this->majorver = substr($this->version,0,$j);
    $this->minorver = substr($this->version,$j+1,strlen($this->version));
  }
  else  {
    $this->majorver = $this->version;
  }
 }
}
//测试程序开始
$test=new browserdetector;
echo $test->ua."<br>";
echo $test->browser."<br>";
echo $test->platform."<br>";
echo $test->version."<br>";
echo $test->majorver."<br>";
echo $test->minorver."<br>";
?>