代码如下：

1. <?php
2. /**
3. * blog.hd001.com Google PageRank Generator
4. *
5. *
6. * @link:    http://blog.hd001.com
7. * @author:  Pasio & superspice <superspice at yeah dot net>
8. * @version: 0.1
9. */
11. @error_reporting(E_ALL ^ E_NOTICE);
13. define('GOOGLE_MAGIC', 0xE6359A60);
15. //unsigned shift right
16. function zeroFill($a, $b)
17. {
18.     $z = hexdec(80000000);
19.         if ($z & $a)
20.         {
21.             $a = ($a>>1);
22.             $a &= (~$z);
23.             $a |= 0x40000000;
24.             $a = ($a>>($b-1));
25.         }
26.         else
27.         {
28.             $a = ($a>>$b);
29.         }
30.         return $a;
31. }   
32.    
33.    
34. function mix($a,$b,$c) {
35.   $a -= $b; $a -= $c; $a ^= (zeroFill($c,13));   
36.   $b -= $c; $b -= $a; $b ^= ($a<<8);   
37.   $c -= $a; $c -= $b; $c ^= (zeroFill($b,13));
38.   $a -= $b; $a -= $c; $a ^= (zeroFill($c,12));
39.   $b -= $c; $b -= $a; $b ^= ($a<<16);
40.   $c -= $a; $c -= $b; $c ^= (zeroFill($b,5));   
41.   $a -= $b; $a -= $c; $a ^= (zeroFill($c,3));    
42.   $b -= $c; $b -= $a; $b ^= ($a<<10);   
43.   $c -= $a; $c -= $b; $c ^= (zeroFill($b,15));
44.     
45.   return array($a,$b,$c);
46. }
47.    
48. function GoogleCH($url, $length=null, $init=GOOGLE_MAGIC) {
49.     if(is_null($length)) {
50.         $length = sizeof($url);
51.     }
52.     $a = $b = 0x9E3779B9;
53.     $c = $init;
54.     $k = 0;
55.     $len = $length;
56.     while($len >= 12) {
57.         $a += ($url[$k+0] +($url[$k+1]<<8) +($url[$k+2]<<16) +($url[$k+3]<<24));
58.         $b += ($url[$k+4] +($url[$k+5]<<8) +($url[$k+6]<<16) +($url[$k+7]<<24));
59.         $c += ($url[$k+8] +($url[$k+9]<<8) +($url[$k+10]<<16)+($url[$k+11]<<24));
60.         $mix = mix($a,$b,$c);
61.         $a = $mix[0]; $b = $mix[1]; $c = $mix[2];
62.         $k += 12;   
63.         $len -= 12;
64.     }
65.    
66.     $c += $length;
67.     switch($len)              /* all the case statements fall through */
68.     {
69.         case 11: $c+=($url[$k+10]<<24);
70.         case 10: $c+=($url[$k+9]<<16);
71.         case 9 : $c+=($url[$k+8]<<8);
72.           /* the first byte of c is reserved for the length */
73.         case 8 : $b+=($url[$k+7]<<24);
74.         case 7 : $b+=($url[$k+6]<<16);
75.         case 6 : $b+=($url[$k+5]<<8);
76.         case 5 : $b+=($url[$k+4]);
77.         case 4 : $a+=($url[$k+3]<<24);
78.         case 3 : $a+=($url[$k+2]<<16);
79.         case 2 : $a+=($url[$k+1]<<8);
80.         case 1 : $a+=($url[$k+0]);
81.          /* case 0: nothing left to add */
82.     }
83.     $mix = mix($a,$b,$c);
84.     /*-------------------------------------------- report the result */
85.     return $mix[2];
86. }
87.    
88. //converts a string into an array of integers containing the numeric value of the char
89. function strord($string) {
90.     for($i=0;$i<strlen($string);$i++) {
91.         $result[$i] = ord($string{$i});
92.     }
93.     return $result;
94. }
95. // http://www.example.com/ - Checksum: 6540747202
97. if (!isset($_GET['url']))
98. {
99.     $url_o   = $_SERVER['HTTP_REFERER'];
100. }
101. else
102. {
103.     $url_o   = $_GET['url'];
104. }
106. $url_o = explode("?", $url_o);
107. $url_o = $url_o[0];
109. $url    = 'info:'.$url_o;
110. $ch     = GoogleCH(strord($url));
111. $url    ='info:'.urlencode($url_o);
112. $cache_filename = "prcache/".urlencode($url_o).".pagerank";
113. // check exists of cache file, if not exists, create it
114. if(!file_exists($cache_filename) || (file_exists($cache_filename) && filemtime($cache_filename) < time() - 86400))
115. {
116.     $url    = "http://toolbarqueries.google.com/search?client=navclient-auto&ch=6$ch&ie=UTF-8&oe=UTF-8&features=Rank&q=$url";
117.     $result = @file_get_contents($url);
118.     $tmp    = @explode(":", $result);
119.     $rank   = intval($tmp[2]);
120.     $handle = fopen ($cache_filename, "w");
121.     flock($handle, LOCK_EX);
122.     fwrite($handle, $rank);
123.     flock($handle, LOCK_UN);
124.     fclose($handle);
125. }
126. $pagerank = @file_get_contents($cache_filename);
127. $pagerank = 2;
128. $width = 6 * $pagerank;
129. $width_ = 6 * (10-$pagerank);
130. echo "document.writeln('<table width=\"80\" border=0 cellpadding=\"0\" cellspacing=\"0\" style=\"font-size:12px\"><tr><td align=\"center\">PageRank</td></tr><tr><td><table width=\"80\" cellpadding=\"0\" cellspacing=\"1\" bgcolor=\"#CCCCCC\" height=\"10\" style=\"font-size:11px\"><tr bgcolor=\"#FFFFFF\"><td width=\"62\"><img src=\"/imgs/bar.gif\" width=\"$width\" height=\"20\"><img src=\"/imgs/space.gif\" width=\"$width_\" height=\"20\"></td><td align=\"center\" style=\"color:red\">$pagerank</td></tr></table></td></tr></table>');";

以上代码保存为pagerank.php到plugins目录下。
实现步骤
一、放一个bar.gif到imgs文件夹下，为上图中的绿色图片，再放一个space.gif到imgs文件夹下，该图片是一个1*1的空白图。
二、在plugins目录下建立prcache目录，并保证该目录为apache执行用户可读写的。
三、调用方法是：
页面中，在你想要显示pagerank的地方加入如下代码
<script language="javascript" src="plugins/pagerank.php"></script>
完毕！