php获取从百度、谷歌等搜索引擎进入网站关键词的方法

<?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];
}
?>