php homemade small paging code

<?php 
ini_set(&#39;memory_limit&#39;,&#39;-1&#39;);
if(!$_GET[&#39;page&#39;])$line=1;
//fy//
else $line=$_GET[&#39;page&#39;];
$f=file("a.pdf");
if(count($f)>500)
{
	for($i=($line-1)*500;$i<$line*500;$i++) 
	{
		echo $f[$i]."<br>";# code...
	}
}
else 
{
	foreach ($f as $key) 
	{
		echo $key."<br>";# code...
	}
}
?>
<meta charset="utf-8">
<title>xiaoshuo</title>
<link rel="stylesheet" href="./assets/css/amazeui.min.css">
<div class="am-g">
  <div class=" col-md-8 col-sm-centered">
    <form class="am-form" action="#" method="get">
      <fieldset class="am-form-set">
        <input type="text" id="page" name="page" placeholder="页数">
      </fieldset>
      <div><button type="submit" class="am-btn am-btn-primary am-btn-block">走你</button></div>
    </form>
  </div>
</div>

The above introduces the PHP self-made small paging code, including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.