php获取网站搜索引擎的关键字

怎么获取其实还是蛮简单的写法：

<?php    function search_word_from() {    $referer = isset($_SERVER['HTTP_REFERER'])?$_SERVER['HTTP_REFERER']:'';    if(strstr( $referer, 'baidu.com')){ //百度        preg_match( "|baidu.+wo?r?d=([^//&]*)|is", $referer, $tmp );        $keyword = urldecode( $tmp[1] );        $from = 'baidu';     }elseif(strstr( $referer, 'google.com') or strstr( $referer, 'google.cn')){ //谷歌        preg_match( "|google.+q=([^//&]*)|is", $referer, $tmp );        $keyword = urldecode( $tmp[1] );        $from = 'google';    }elseif(strstr( $referer, 'so.com')){ //360搜索        preg_match( "|so.+q=([^//&]*)|is", $referer, $tmp );        $keyword = urldecode( $tmp[1] );        $from = '360';    }elseif(strstr( $referer, 'sogou.com')){ //搜狗        preg_match( "|sogou.com.+query=([^//&]*)|is", $referer, $tmp );        $keyword = urldecode( $tmp[1] );        $from = 'sogou';     }elseif(strstr( $referer, 'soso.com')){ //搜搜        preg_match( "|soso.com.+w=([^//&]*)|is", $referer, $tmp );        $keyword = urldecode( $tmp[1] );        $from = 'soso';    }else {        $keyword ='';        $from = '';    }        return array('keyword'=>$keyword,'from'=>$from);}    //以下为测试//在搜索引擎搜索个关键词，进入网站$word = search_word_from();if(!empty($word['keyword'])){    echo '关键字：'.$word['keyword'].' 来自：'.$word['from'];}?>