使用AJAX / JSON / Jquery在数据库中插入数据

Question

I'm trying to create a small chat application but for the sake of minifying the bytes being transferred is there any other way on writing this javascript that is less heavy than this code?

Here is my javascript:

function sendChatText() {

                if (sendReq.readyState == 4 || sendReq.readyState == 0) {
                    sendReq.open("POST", 'includes/getChat.php?last=' + lastMessage, true);
                    sendReq.setRequestHeader('Content-Type','application/x-www-form-urlencoded');
                    sendReq.onreadystatechange = AjaxRetrieve();  
                    var param = 'message=' + document.getElementById('txtA').value;
                    param += '&name='+user;
                    param += '&uid='+uid;
                    param += '&rid='+document.getElementById('trg').value;
                    sendReq.send(param);
                    document.getElementById('txtA').value = '';
                }                           
            }

Can this also be done on a JSON format too? because I think some says that json is lighter.. not sure though

here is my php code

$con = new PDO("mysql:host=". db_host .";dbname=chat_db", db_username , db_password);
$con->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION );
$sql = "SELECT * FROM users WHERE id = :rid LIMIT 1";
$stmt=$con->prepare($sql);
$stmt->bindValue( 'rid',$_POST['rid'], PDO::PARAM_STR);
$stmt->execute();
    foreach($stmt->fetchAll()as $res)
        {
            $usern = $res['username'];
            $user_lvl = $res['ulvl'];
        }
$text=$_POST['message'];
$sql4 = "INSERT INTO $tblname2(msgid,username,message_content,message_time,recipient)VALUES(:aid,:a,:b,NOW(),:c) ";
                    $stmt5 = $con2->prepare($sql4);
                    $stmt5->bindParam(':aid',$tblpre,PDO::PARAM_STR);
                    $stmt5->bindParam(':a',$_POST['name'],PDO::PARAM_STR);
                    $stmt5->bindParam(':b',$text,PDO::PARAM_STR);
                    $stmt5->bindParam(':c',$usern,PDO::PARAM_STR);
                    $stmt5->execute();

Answer 1

As user2401175 saies. Why not use a framework, thats what they are here for.

jQuery is really simple and easy to understand.

You could try adding this, just before your "" tag.

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>

Under this include of jQuery, you may now use the jQuery Post method to do your ajax request.

Answer 2

In html Use

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>

then Create javascript object like this

var changePacket = {
date1:value1,
data2:value2
}

And send Ajax request

$.ajax({
    url: "phpFile.php",
    dataType: 'json',
    type: 'POST',
    data: {json:JSON.stringify(changePacket)},
    success: function(response) {
     alert('hip hip hurray');
    },
    error: function(response) {
     alert('some thing wrong happend');
    }
});

In php

$json = $_POST['json'];
$data = json_decode($json);

now user your variable like this $date->data1 and $date->data2