服务器上的文件可以由客户端控制吗?

So I have a text file with a number inside. This text file is saved on the server. When ever someone downloads a file of mine, I have the number increase one. I know earlier today, the total count was 87. But I just checked minutes ago and it showed up at 11.

Anyone know what can be the cause of this and how I can avoid the number being inaccurate? Here is the php code I used so that the number in the text file increases.

 <html>
<head>
    <title>Downloading False Logics</title>
</head>
<body onload="SendFile()">
    <script language="JavaScript">
        window.name = 'main';
        function SendFile() {
        window.location.href = "Downloadable/False%20Logics.exe";
        }
    </script>
    <?
        define("HITCOUNT", "fldownloadcount.txt");
        /*design by Mark Le Roy @ http://www.helpvid.net*/
        function addOne() {
        $fh = fopen(HITCOUNT, "r");
        $count = fread($fh, filesize(HITCOUNT));
        fclose($fh);

        $count = $count +1;

        $fh = fopen(HITCOUNT, "w");
        fwrite($fh, $count);
        fclose($fh);
        }


        /* count Variables */
        function getcount() {
        $fh = fopen(HITCOUNT, "r");
        $count = fread($fh, filesize(HITCOUNT));
        fclose($fh);

        /* display Variables */
        return $count;
        }
        addOne();
        echo "This has been downloaded ";
        echo getCount(); 
        echo " times now since 1/16/2016."
    ?>
</body>