How to delete complete HTML content?

Question

I’m doing a chat using PHP, Javascript, Ajax and HTML. I know it’s not the best option, but I chose to create an html file log.html which stores all messages and is loaded by my PHP file index.php. All messages are sent to the log through the file post.php. I need to delete all messages, i.e., delete all the html content present in log.html at a certain time. How can I do this? Follow the file code.

Index.php

/* Tentando apagar o conteúdo do arquivo */
$var = date('H:i:s');
if ($var == '02:00:00') {
    $fp = fopen("log.html", 'w');
    fwrite($fp, "");
    fclose($fp);
}

<!-- Dentro do HTML da página -->
<div class="chatlogs">
    <!--    mensagens vem pra cá     -->
</div>
<!-- mensagem que será enviada -->
<form class="chat-form" name="message" action="">
    <textarea name="usermsg" id="usermsg"></textarea>
    <button name="submitmsg" type="submit" id="submitmsg"><i class="fa fa-paper-plane"></i></button>
</form>

// JS && Ajax da página
function loadLog() {
    var a = $(".chatlogs").attr("scrollHeight") - 20;
    $.ajax({
        url: "log.html",
        cache: !1,
        success: function(t) {
            $(".chatlogs").html(t);
            var o = $(".chatlogs").attr("scrollHeight") - 20;
            a < o && $(".chatlogs").animate({
                scrollTop: o
            }, "normal")
        }
    })
}
$(document).ready(function() {}), $("#submitmsg").click(function() {
    var t = $("#usermsg").val();
    return $.post("post.php", {
        text: t
    }), $("#usermsg").attr("value", ""), !1
}), setInterval(loadLog, 1e3);

Post.php

<?php
    /* Envio da mensagem para o log.html */
    session_start();
    if(isset($_SESSION['usuarioUsuario'])){
        $text = $_POST['text'];
        $fp = fopen("log.html", 'a');
        if ($_SESSION["usuarioNivel"] == 9) {
            fwrite($fp, "<div class='chat self'><div class='user-photo'><img src='../../dist/img/perfil/" . $_SESSION['usuarioImagem'] . "'></div><p class='chat-message'><span class='user'>~".$_SESSION['usuarioUsuario']."</span>".stripslashes(htmlspecialchars($text))." <span class='hora'>".date("g:i A")."</span><br></p></div>");
        } else {
            fwrite($fp, "<div class='chat friend'><div class='user-photo'><img src='../../dist/img/perfil/" . $_SESSION['usuarioImagem'] . "'></div><p class='chat-message'><span class='user'>~".$_SESSION['usuarioUsuario']."</span>".stripslashes(htmlspecialchars($text))." <span class='hora'>".date("g:i A")."</span><br></p></div>");
        }
    fclose($fp);
    }
?>

How I erase all the contents of log.html at a certain time without needing a user interaction?

Answer 1

Erase

$var = date('H:i:s');
if (strtotime($var) < strtotime('09:34:00') && strtotime($var) > strtotime('15:00:00')) {
    $fp = fopen("log.html", 'w');
    fwrite($fp, "");
    fclose($fp);
}

that strtotime() reduces the time to "int" and after that it checks a time to do the deletion but indicate for a distance time for if there is some delay not cancel your deletion, you can by a cornjob if you want to automate...

Delete /cornjob

    $fp = fopen("log.html", 'w');
    fwrite($fp, "");
    fclose($fp);