ajax和php之间的数组json

Question

I'm developing a simple guestbook and I want to update the table with all messages without refreshing the page because if someone it's writing a comment and the page refreshes the comment will be lost. So I began writing some code with ajax to update the table but I don't know how to send an array (with comment, username, date ecc) from php to ajax. In the database I have a column named "wrote" and it can be 0 (unread) or 1 (read). 1 it's when the messages it's already on the table. This is what I've done since now, maybe it's wrong

getGuest.php

<?php

include("Database.php");

$Database = new Database( "localhost", "root", "1234");
$Database->connectToServer();
$Database->connectToDatabase("test");

$result = $Database->unreadMessages();

$rows=mysql_fetch_array($result);

echo json_encode($rows);
?>

Script.js

window.onload = function(){
    interval = window.setInterval('updateGuest()',5000);
}



function updateGuest() {
    $.ajax({
        url: 'getGuest.php',
        method: 'get',
        success: on_getGuest_success,
        error: on_error
    });
}

function on_getGuest_success(data) {
    for(var i=0; i<data.length;i++) {
       // HERE I WANT TO ADD A ROW WITH ALL MESSAGE UNREAD BUT I DONT KNOW WHAT I HAVE TO DO
    }

}

function on_error() {
    //do something

}

Answer 1

1. Make sure the JSON contains an array
2. Add headers
3. use getJSON

Like this:

PHP

$data = array(); 
while ($row = mysql_fetch_assoc($result)) { 
  $data[] = $row; 
} 
header("content-type: application/json");
echo json_encode($data);

JS:

$(function() { // when page has loaded
  var tId = setInterval(function() { // save the tId to allow to clearTimeout if needed
    $.getJSON("getGuest.php",function(data) { // call the server using jQuery's JSON access
      $('.guestbook').empty(); // empty the container
      var rows = []; // create an array to hold the rows
      $.each(data,function(_,item) { // loop over the returned data adding rows to array
        rows.push('<tr><td class="name" width="10%">' + item.name + '</td></tr>');
     });
     $('.guestbook').html(rows.join()); // insert the array as a string
    });
  },5000); // every 5 secs
});

I would personally only return what was new since last time