php获取来访者在搜索引擎搜索某个关键词，进入网站

<?php
//获取来访者在搜索引擎搜索某个关键词，进入网站
$word = search_word_from();
if(!empty($word['keyword']))
{
    echo '关键字：'.$word['keyword'].' 来自：'.$word['from'];
}
 
 
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);
}