在访客从搜索引擎而来的第一个页面上显示访客搜索的关键词，根据这个关键词做出一些提高网站交互能力的改变，比如显示这个关键词相关的其它文章

以下是相关实现代码： 代码如下: <?php /* Plugin Name: display-search-keywords Plugin URI: http://www.imyxiao.com/1531.html Description: 当访客通过搜索引擎来到你的博客，这个插件可以显示访客搜索的关键词 Version: 1.0 Author:<a href="http://www.imyxiao.com/">仰肖</a> */ function unescape($str) {  $ret = '';  $len = strlen($str);  for ($i = 0; $i < $len; $i++) {   if ($str[$i] == '%' && $str[$i +1] == 'u') {    $val = hexdec(substr($str, $i +2, 4));    if ($val < 0x7f)     $ret .= chr($val);    else     if ($val < 0x800)      $ret .= chr(0xc0 | ($val >> 6)) . chr(0x80 | ($val & 0x3f));     else      $ret .= chr(0xe0 | ($val >> 12)) . chr(0x80 | (($val >> 6) & 0x3f)) . chr(0x80 | ($val & 0x3f));      $i += 5;   } else    if ($str[$i] == '%') {     $ret .= urldecode(substr($str, $i, 3));     $i += 2;    } else     $ret .= $str[$i];  }  return $ret; } function ls_get_delim($ref) {  $search_engines = array (   'google.com.hk' => 'q',   'google.com.tw' => 'q',   'go.google.com' => 'q',   'google.com' => 'q',   'blogsearch.google.com' => 'q',   'cn.bing.com' => 'q',   'one.cn.yahoo.com' => 'p',   'baidu.com' => 'wd',   'soso.com' => 'w',   'youdao.com' => 'q',   'sogou.com' => 'query'  );  $delim = false;  // 判断  if (isset ($search_engines[$ref])) {   $delim = $search_engines[$ref];  }  return $delim; }   function ls_get_refer() {  // 判断前一页面的 URL 地址  $queryString = $_GET['referer'];  $queryString = unescape($queryString);  if (!isset ($queryString) || ($queryString == ''))   return false;  $referer_info = parse_url($queryString);  $referer = $referer_info['host'];  //去除www.  if (substr($referer, 0, 4) == 'www.')   $referer = substr($referer, 4);  return $referer; }   function ls_getinfo($what) {  $referer = ls_get_refer();  if (!$referer)   return false;  $delimiter = ls_get_delim($referer);  if ($delimiter) {   $terms = ls_get_terms($delimiter);   if ($what == 'isref' && $terms != '') {    return true;   }   if ($what == 'terms') {    echo $terms;   }  }  return false; }   function yxiao_seems_utf8($str) {  $length = strlen($str);  for ($i = 0; $i < $length; $i++) {   $c = ord($str[$i]);   if ($c < 0x80)    $n = 0; # 0bbbbbbb   elseif (($c & 0xE0) == 0xC0) $n = 1; # 110bbbbb   elseif (($c & 0xF0) == 0xE0) $n = 2; # 1110bbbb   elseif (($c & 0xF8) == 0xF0) $n = 3; # 11110bbb   elseif (($c & 0xFC) == 0xF8) $n = 4; # 111110bb   elseif (($c & 0xFE) == 0xFC) $n = 5; # 1111110b   else    return false; # Does not match any model   for ($j = 0; $j < $n; $j++) { # n bytes matching 10bbbbbb follow ?    if ((++ $i == $length) || ((ord($str[$i]) & 0xC0) != 0x80))     return false;   }  }  return true; }   function ls_get_terms($d) {  //取得查询值  $queryString = $_GET['referer'];  $queryString = unescape($queryString);  $query_str = parse_url($queryString);  parse_str($query_str[query], $query_str);  $query = $query_str[$d];  $query = urldecode($query);    $query = str_replace("'", '', $query);  $query = str_replace('"', '', $query);  $query_array = preg_split('/[s,+.]+/', $query);  $query_terms = implode(' ', $query_array);  $terms = htmlspecialchars($query_terms);  //gbk->utf8  if (!yxiao_seems_utf8($terms)) {   $terms = iconv("GBK", "UTF-8//IGNORE", $terms);  }  return $terms; } if (ls_getinfo('isref')) { ?> document.write('<div id="serp"><p>') document.write('更多搜索结果：<em><a href="http://www.jb51.net/search?q=<?php ls_getinfo(terms); ?>" ') document.write('title="查看<?php ls_getinfo(terms); ?>的搜索结果" rel="nofollow"><?php ls_getinfo(terms); ?></a></em>') document.write('</p></div>'); <?php } ?>