PHP擷取搜尋索引鍵有關問題

PHP擷取搜尋索引鍵問題
網上找了一段代碼想實現擷取搜尋關健字，測試了一個關健字取不了，是不是這代碼無效了，還是那裡有BUG？

//取搜尋來源關健字

function get_keyword($url,$kw_start)
{
$start=stripos($url,$kw_start);
$url=substr($url,$start+strlen($kw_start));
$start=stripos($url,'&');
if ($start>0)
{
$start=stripos($url,'&');
$s_s_keyword=substr($url,0,$start);
}
else
{
$s_s_keyword=substr($url,0);
}
return $s_s_keyword;
}
$url=isset($_SERVER['HTTP_REFERER'])?$_SERVER['HTTP_REFERER']:'';//擷取入站url。





$search_1="google.com.hk"; //q= utf8
$search_2="baidu.com"; //wd= gbk
$search_3="yahoo.cn"; //q= utf8
$search_4="sogou.com"; //query= gbk
$search_5="soso.com"; //w= gbk
$search_6="bing.com"; //q= utf8
$search_7="youdao.com"; //q= utf8
$search_8="so.com"; //q= utf8


$google=preg_match("/\b{$search_1}\b/",$url);//記錄匹配情況，用於入站判斷。
$baidu=preg_match("/\b{$search_2}\b/",$url);
$yahoo=preg_match("/\b{$search_3}\b/",$url);
$sogou=preg_match("/\b{$search_4}\b/",$url);
$soso=preg_match("/\b{$search_5}\b/",$url);
$bing=preg_match("/\b{$search_6}\b/",$url);
$youdao=preg_match("/\b{$search_7}\b/",$url);
$so=preg_match("/\b{$search_8}\b/",$url);
$s_s_keyword="";
// $bul=$_SERVER['HTTP_REFERER'];
$bul=$_REQUEST["comelink"];
//擷取沒參數網域名稱
preg_match('@^(?:http://)?([^/]+)@i',$bul,$matches);
$burl=$matches[1];
//匹配網域名稱設定
$curl="www.hcyf07.com";


if($burl!=$curl){
if ($google)
{//來自google
$s_s_keyword=get_keyword($url,'q=');//關鍵詞前的字元為"q="。
$s_s_keyword=urldecode($s_s_keyword);
$urlname="Google：";
$_SESSION["urlname"]=$urlname;
$_SESSION["s_s_keyword"]=$s_s_keyword;
//$s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎為gbk
}
else if($baidu)
{//來自百度
$s_s_keyword=get_keyword($url,'wd=');//關鍵詞前的字元為"wd="。
$s_s_keyword=urldecode($s_s_keyword);
$s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎為gbk
$urlname="百度：";
$_SESSION["urlname"]=$urlname;
$_SESSION["s_s_keyword"]=$s_s_keyword;
}
else if($yahoo)
{//來自雅虎
$s_s_keyword=get_keyword($url,'q=');//關鍵詞前的字元為"q="。
$s_s_keyword=urldecode($s_s_keyword);
//$s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎為gbk
$urlname="雅虎：";
$_SESSION["urlname"]=$urlname;
$_SESSION["s_s_keyword"]=$s_s_keyword;
}
else if($sogou)
{//來自搜狗
$s_s_keyword=get_keyword($url,'query=');//關鍵詞前的字元為"query="。
$s_s_keyword=urldecode($s_s_keyword);
$s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎為gbk
$urlname="搜狗：";
$_SESSION["urlname"]=$urlname;
$_SESSION["s_s_keyword"]=$s_s_keyword;
}
else if($soso)
{//來自搜搜
$s_s_keyword=get_keyword($url,'w=');//關鍵詞前的字元為"w="。
$s_s_keyword=urldecode($s_s_keyword);
$s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎為gbk
$urlname="搜搜：";
$_SESSION["urlname"]=$urlname;
$_SESSION["s_s_keyword"]=$s_s_keyword;
}
else if($bing)
{//來自必應
$s_s_keyword=get_keyword($url,'q=');//關鍵詞前的字元為"q="。
$s_s_keyword=urldecode($s_s_keyword);
//$s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎為gbk
$urlname="必應：";
$_SESSION["urlname"]=$urlname;
$_SESSION["s_s_keyword"]=$s_s_keyword;
}
else if($so)
{//來自360
$s_s_keyword=get_keyword($url,'q=');//關鍵詞前的字元為"q="。
$s_s_keyword=urldecode($s_s_keyword);
//$s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎為gbk
$urlname="360：";
$_SESSION["urlname"]=$urlname;
$_SESSION["s_s_keyword"]=$s_s_keyword;
}
else if($youdao)
{//來自有道
$s_s_keyword=get_keyword($url,'q=');//關鍵詞前的字元為"q="。
$s_s_keyword=urldecode($s_s_keyword);
//$s_s_keyword=iconv("GBK","UTF-8",$s_s_keyword);//引擎為gbk
$urlname="有道：";
$_SESSION["urlname"]=$urlname;
$_SESSION["s_s_keyword"]=$s_s_keyword;
}
else{
// $urlname=$burl;
$urlname="直接存取";
$s_s_keyword="";
$_SESSION["urlname"]=$urlname;
$_SESSION["s_s_keyword"]=$s_s_keyword;
}
$s_urlname=$urlname;

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