首先学东西  要多看手册
用php自带的函数  可以解决一些难解的问题 

<?php
/**
 * Created by JetBrains PhpStorm.
 * User: Administrator
 * Date: 13-6-11
 * Time: 上午11:43
 * To change this template use File | Settings | File Templates.
 */
header("Content-type:text/html;charset=utf-8");
$array =array (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,20,21,22,23,24,25);
$page=$_GET['page']?(int)$_GET['page']:'0';
$size=5;
$pnum = ceil(count($array) / $size);
$newArray = array_slice($array,($page-1)*$size,$size);
foreach($newArray as $key=>$val)
{
    echo "<a href=\"array1.php?catid=$key.html\" target=\"_blank\">$val</a>\n";
}
echo "<br/><br/><br/><br/>";
echo "<a href=?>第一页</a>\n";
$str='';
for($i=1;$i<=$pnum-1;$i++)
{
 
   echo "<a href=\"?page=$i\" target=\"_blank\"";
   if($i==$page){echo "style='color:red;'";};
   echo ">$i</a>\n\n";
 
}
echo "<a href=?page=$pnum>最后一页</a>\n";
?>