<?php session_start();error_reporting(E_ALL);header("content-type:text/html;charset=UTF-8;"); ?>
<script type="text/javascript">
function mail()
{

    var a, b; 
    a = "<?php 
              $file = file_get_contents('database.txt');
              $kol = explode("|", $file);
              $kol = count($kol);
              if(!isset($_SESSION['mails']))
              {
                  $_SESSION['mails'] = $kol;
                  echo $kol;
              }else{
                  echo $kol;
              }
        ?>";
    b = "<?php echo $_SESSION['mails']; ?>";

    if(a > b)
    {
        alert("Вам пришло новое письмо");
    }

}
setInterval("mail()", '1000');
</script>

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