Browser inspection class implemented in PHP_php skills

<&#63;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>";
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