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);
}