Need A Little Help :)

[MatthewRidings]

Hi all iv'e been attempting to code up a shout box for my site basically iv'e coded it all up and it works great apart from the posting side of things it will post the time and the user that's logged in but its not posting the message into the log file and that is what I'm currently struggling to fix might be a simple fix but Iv'e not done any coding for along time and though I'd try getting back into it any help would be great

here is a screen shot to what I get when I post

 

the chat.php

<?php
include 'include/database.php';
if(!isset($_SESSION['signed_in'])){
}
else{
?>
<div id="chatwrapper">
<div id="chatmenu">
 <p class="welcome">Welcome, <b><?php echo $_SESSION['user_name']; ?></b></p>
 <div style="clear:both"></div>
</div>
<div id="chatbox"><?php
if(file_exists("log.html") && filesize("log.html") > 0){
 $handle = fopen("log.html", "r");
 $contents = fread($handle, filesize("log.html"));
 fclose($handle);

 echo $contents;
}
?></div>

<form name="message" action="">
 <input name="usermsg" type="text" id="usermsg" size="63" />
 <input name="submitmsg" type="submit"  id="submitmsg" value="Send" />
</form>
</div>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
<script type="text/javascript">
// jQuery Document
$(document).ready(function(){
//If user submits the form
$("#submitmsg").click(function(){
 var clientmsg = $("#usermsg").val();
 $.post("post.php", {text: clientmsg});   
 $("#usermsg").attr("value", "");
 return false;
});

//Load the file containing the chat log
function loadLog(){ 
 var oldscrollHeight = $("#chatbox").attr("scrollHeight") - 20;
 $.ajax({
  url: "log.html",
  cache: false,
  success: function(html){ 
   $("#chatbox").html(html); //Insert chat log into the #chatbox div   
   var newscrollHeight = $("#chatbox").attr("scrollHeight") - 50;
   if(newscrollHeight > oldscrollHeight){
 $("#chatbox").animate({ scrolltop: newscrollHeight }, 'normal'); //Autoscroll to bottom of div
   }   
    },
 });
}
setInterval (loadLog, 2500); //Reload file every 2.5 seconds
});
</script>
<?php
}
?>

 

this is the post.php

 

<?
session_start();


if(isset($_SESSION['user_name'])){
$text = $_POST['text'];

$fp = fopen("log.html", 'a');
fwrite($fp, "<div class='msgln'>(".date("g:i A").") <b>".$_SESSION['user_name']."</b>: ".stripslashes(htmlspecialchars($text))."<br></div>");
fclose($fp);
}
?>

 

Personally I think its trying to post to the message to the database which I don't want it to do as it suppose to post to the html log file.