per http://www.reddit.com/r/PHPhelp/comments/1mgw65/variable_isnt_being_passed_i_think/

converse.php

<?php
    $site_root = $_SERVER["SERVER_NAME"];
    $serverRoot = $_SERVER["DOCUMENT_ROOT"] . '/';
    spl_autoload_register(function ($class) {
        global $serverRoot;
        require_once $serverRoot . 'classes/' . $class . '.class.php';
    });

    if ( ! isset($_SESSION)) {
        session_start();
    }

    require_once $serverRoot . 'include/time.php';
    if ( ! isset($yours)) {
        $yours = unserialize($_SESSION["Character"]);
    }

    $chat = new Conversation($yesterday->format('Y-m-d H:i:s'),1); // '1' needs to be replaced with the character's location'

    $currentChar = $_SESSION["CharUID"];

    if (isset($_POST["UD_type"])) {
        if ($_POST["UD_type"]="Converse") {
            $newComment = $_POST["Comm"];
            $chat->Send($sendChat,$yours->UID,$newComment);
        }
    }
?>
<?php echo $chat ?>
<input type='text' name='Comm' class='TalkBox' id='message' onkeypress='return typeChat(event)'>
<input type='submit' value='Talk' class='TalkButton' onClick='chat()'>

time.php

<?php
    if ( ! isset($_SESSION)) {
        session_start();
    }

    $t=time(); // Current Time
    $u=$t;
    $tf = date('Y-m-d g:i A',$t); // Time, Formatted (in server TZ) (To be displayed)
    $tu = date('Y-m-d G:i:s',$t); // Time, Formatted (in server TZ) (For the update process)
    $tfOld = "'" . date('Y-m-d G:i:s',$t-86400) . "'"; // Time minus 1 day, formatted. For use in pulling conversations.
    if (isset($_SESSION["TZ"])) // If the user has set a TimeZone
    {
        $tz=date_create(date('Y-m-d g:i:s',$t),timezone_open($_SESSION["TZ"])); // Timezone
        $t=$t+date_offset_get($tz); // Time, modified to be accurate to Timezone
        $tf = date('Y-m-d g:i A',$t); // Time, Formatted (in User TZ) (to be displayed)
    }
    $tzOffset=($u-$t); // Number of seconds difference from server (UTC) to user

    $date = new DateTime();
    $localTime = new DateTime('now',new DateTimeZone('America/Los_Angeles'));
    /** @noinspection PhpVoidFunctionResultUsedInspection */
    /** @noinspection PhpParamsInspection */
    $yesterday = $date->sub(date_interval_create_from_date_string('1 day'));