使用JQuery

Question

我正在我的网站上进行聊天，我的代码允许用户输入文本并按Enter键提交。输入与使用php将输入写入文件一起工作，但是应该将文件中的输入添加到其中的函数似乎不起作用。它会添加用户的昵称，但不会显示用户输入的消息。我究竟做错了什么？

我已经尝试过2天了。先感谢您！

的Javascript / JQuery的：

    var instanse = false;
    var file = 'data.txt'
    function Chat() {
        /* call update chat function */
        this.update = updateChat;
        /* call send chat function */
        this.send = sendChat;
        /* call get state function */
        this.getState = getState;
    }
    //define get state function
    function getState() {
        if(!instanse){
            instanse = true;
            /* define AJAX function */
            $.ajax({
                type: "POST",
                url: "ajax.php",
                data: {'function': 'getState', 'file': file},
                dataType: "json",  
                success: function(data) {state = data.state;instanse = false;}
            });
        }
    }
    //define update chat function
    function updateChat() {
        if(!instanse){
            instanse = true;
            /* define AJAX function */
            $.ajax({
                type: "POST",
                url: "ajax.php",
                data: {'function': 'update','state': state,'file': file},
                dataType: "json",
                success: function(data) {
                    if(data.text){
                        /* manage data */
                        for (var i = 0; i < data.text.length; i++) {
                            $('#chat-row').append($(""+ data.text[i] +""));
                        }  
                    }
                    /* manage position of current chat */
                    document.getElementById('chat-row').scrollTop = document.getElementById('chat-row').scrollHeight;
                    instanse = false;
                    state = data.state;
                }
            });
        }
        else {
        setTimeout(updateChat, 1000);
        }
    }
    //define send chat function
    function sendChat(msg, name) { 
        updateChat();
        /* define AJAX function */
        $.ajax({
            type: "POST",
            url: "ajax.php",
            /* manage message */
            data: {'function': 'send','message': msg,'nickname': name,'file': file},
            dataType: "json",
            success: function(data){
                updateChat();
            }
        });
    }
//--------------------
    // open popup prompt for ask name of user    
        var name = prompt("Enter your name:", "Guest");
        // default name is 'Guest'
        if (!name || name === ' ') {
            name = "Guest";  
        }
        // strip tags
        name = name.replace(/(<([^>]+)>)/ig,"");
        // display name on page
        $("#user-name").html("User: <strong>" + name + "</strong>");
        var chat = new Chat()
        $(function() {
            chat.getState(); 
            /* define function when key presses */
            $("#posttext").keydown(function(event) {  
                var key = event.which;  
                /* if key including return. */
                if (key >= 33) {
                    var maxLength = $(this).attr("maxlength");  
                    var length = this.value.length;  
                    /* define limit of new content */
                    if (length >= maxLength) {  
                        event.preventDefault();  
                    }  
                }  
            });
            /* define function when key release */
            $('#posttext').keyup(function(e) {  
                if (e.keyCode == 13) { 
                    var text = $('#posttext').val();
                    var maxLength = $(this).attr("maxlength");  
                    var length = text.length; 
                    // send 
                    if (length <= maxLength + 1) { 
                        chat.send(text, name);  
                        $(this).val("");
                    } 
                    else {
                        $(this).val(text.substring(0, maxLength));
                    }  
                }
            });
        });

PHP：

<?php
$function = $_POST['function'];
$log = array();
switch($function) {
    /* get state case */
    case('getState'):
        /* check file available or not */
        if (file_exists('data.txt')) {
            /* assign to variable */
            $lines = file('data.txt');
        }
        $log['state'] = count($lines); 
        break;
    /* update case */
    case('update'):
        $state = $_POST['state'];
        /* check file available or not */
        if (file_exists('data.txt')) {
            /* assign to variable */
            $lines = file('data.txt');
        }
        $count =  count($lines);
        if ($state == $count){
            /* if state & count are equal */
            $log['state'] = $state;
            $log['text'] = false;
        } else {
            /* if state & count are no equal */
            $text= array();
            $log['state'] = $state + count($lines) - $state;
            foreach ($lines as $line_num => $line) {
                if ($line_num >= $state){
                    $text[] =  $line = str_replace("\n", "", $line);
                }
            }
            $log['text'] = $text; 
        }
        break;
    /* send case */
    case('send'):
        $nickname = htmlentities(strip_tags($_POST['nickname']));
        $reg_exUrl = "/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\/\S*)?/";
        $message = htmlentities(strip_tags($_POST['message']));
        if (($message) != "\n") {
            if (preg_match($reg_exUrl, $message, $url)) {
                $message = preg_replace($reg_exUrl, '<a href="'.$url[0].'" target="_blank">'.$url[0].'</a>', $message);
            } 
            fwrite(fopen('data.txt', 'a'), "<div>". $nickname . "</div> \n" . $message);
        }
        break;
}

echo json_encode($log);