PHP分页

<?php
$db=new mysqli();
$db->connect('localhost','root','root','test');
$sql="select count(*) from user";
$res=$db->query($sql);
$row=$res->fetch_row();
$pg_size=3;
$row_total=$row[0];
$pg_total=ceil($row_total/$pg_size);
$pg_now=@$_GET['pg_now']?$_GET['pg_now']:1;
$sql="select * from user limit ".($pg_now-1)*$pg_size.",".$pg_size;
$res=$db->query($sql);
$rows=$res->fetch_all(MYSQLI_ASSOC);
?>
<center>
<table width="400"  border="1">
<tr bgcolor="#ccc"><th>ID</th><th>name</th><th>pass</th></tr>

<?php
foreach($rows as $v){
    echo "<tr>";
    echo "<td>{$v['id']}</td>";
    echo "<td>{$v['name']}</td>";
    echo "<td>{$v['pass']}</td>";
    echo "</tr>";
}
?>
</table>
<?php

echo "<br>当前页：".$pg_now.'/'.$pg_total.' &nbsp;&nbsp;';
if($pg_now==1){
    echo "上一页";
}else{
    $pre_pg=$pg_now-1;
    echo "<a href='paginate.php?pg_now={$pre_pg}'>上一页</a> ";
}
for($i=1;$i<=$pg_total;$i++){
    echo " &nbsp;&nbsp;<a href='paginate.php?pg_now={$i}'>{$i}</a>";
}

if($pg_now==$pg_total){
    echo " &nbsp;&nbsp;下一页";
}else{
    $next_pg=$pg_now+1;
    echo " &nbsp;&nbsp;<a href='paginate.php?pg_now={$next_pg}'>下一页</a> ";
}
echo "<br><br>";

?>
<form action="paginate.php" method="get">
跳转到：<input type="text" name="pg_now">
<input type="submit" value="GO">
</form>
</center>

效果图：

说明：

当当前页为第一页或最后一页的时候，上一页或下一页不能点击，实现代码：

if($pg_now==1){
	echo "上一页";
}else{
	$pre_pg=$pg_now-1;
	echo "<a href='paginate.php?pg_now={$pre_pg}'>上一页</a> ";
}

　　

if($pg_now==$pg_total){
	echo "   下一页";
}else{
	$next_pg=$pg_now+1;
	echo "   <a href='paginate.php?pg_now={$next_pg}'>下一页</a> ";
}

　　问题：

页码数过多怎么控制？