custom notification when new record is added in database php-jquery

JS Code (this query use header file)

<script type="text/javascript">
var old_count = -1;

setInterval(function(){    
    $.ajax({
        type : "POST",
        url : "file.php",
        success : function(data){
if ( old_count != -1 && data > document.getElementById('hiddenfiled').value){
old_count=data;
document.getElementById('hiddenfiled').setAttribute('value',data);
alert("New employee added");
}
else
{
old_count=data;
document.getElementById('hiddenfiled').setAttribute('value',data);

}

}
//alert(data);
        
    });
},1000);

</script>


And the PHP code:  (file name: file.php)

<?php
include("config.php");


$sql = "SELECT COUNT(*) as count FROM `tblemployee`";
$qry = mysql_query($sql);
$row = mysql_fetch_assoc($qry);
echo $row['count'];

?>