Using ajax to display new database inputs without refreshing the page - javascript

I am using ajax to post comments to a certain page, I have everything working, except for when the user posts a comment I would like it to show immediately without refreshing. The php code I have to display the comments is:
<?php
require('connect.php');
$query = "select * \n"
. " from comments inner join blogposts on comments.comment_post_id = blogposts.id WHERE blogposts.id = '$s_post_id' ORDER BY comments.id DESC";
$result = mysql_query($query);
while ($row = mysql_fetch_array($result)) {
$c_comment_by = $row['comment_by'];
$c_comment_content = $row['comment_content'];
?>
<div class="comment_box">
<p><?php echo $c_comment_by;?></p>
<p><?php echo $c_comment_content;?></p>
</div>
<?php } ?>
</div>
</div>
<?php
}
}
and the code I have to post comments is:
<?php
$post_comment = $_POST['p_post_comment'];
$post_id = $_POST['p_post_id'];
$post_comment_by = "Undefined";
if ($post_comment){
if(require('connect.php')){
mysql_query("INSERT INTO comments VALUES (
'',
'$post_id',
'$post_comment_by',
'$post_comment'
)");
echo " <script>$('#post_form')[0].reset();</script>";
echo "success!";
mysql_close();
}else echo "Could no connect to the database!";
}
else echo "You cannot post empty comments!"
?>
JS:
function post(){
var post_comment = $('#comment').val();
$.post('comment_parser.php', {p_post_comment:post_comment,p_post_id:<?php echo $post_id;?>},
function(data)
{
$('#result').html(data);
});
}
This is what I have for the refresh so far:
$(document).ready(function() {
$.ajaxSetup({ cache: false });
setInterval(function() {
$('.comment_box').load('blogpost.php');
}, 3000);.
});
Now what I want to do is to use ajax to refresh the comments every time a new one is added. Without refreshing the whole page, ofcourse. What am I doing wrong?

You'll need to restructure to an endpoint structure. You'll have a file called "get_comments.php" that returns the newest comments in JSON, then call some JS like this:
function load_comments(){
$.ajax({
url: "API/get_comments.php",
data: {post_id: post_id, page: 0, limit: 0}, // If you want to do pagination eventually.
dataType: 'json',
success: function(response){
$('#all_comments').html(''); // Clears all HTML
// Insert each comment
response.forEach(function(comment){
var new_comment = "<div class="comment_box"><p>"+comment.comment_by+"</p><p>"+comment.comment_content+"</p></div>";
$('#all_comments').append(new_comment);
}
})
};
}
Make sure post_id is declared globally somewhere i.e.
<head>
<script>
var post_id = "<?= $s_post_id ; ?>";
</script>
</head>
Your new PHP file would look like this:
require('connect.php');
$query = "select * from comments inner join blogposts on comments.comment_post_id = blogposts.id WHERE blogposts.id = '".$_REQUEST['post_id']."' ORDER BY comments.id DESC";
$result = mysql_query($query);
$all_comments = array() ;
while ($row = mysql_fetch_array($result))
$all_comments[] = array("comment_by" => $result[comment_by], "comment_content" => $result[comment_content]);
echo json_encode($all_comments);
Of course you'd want to follow good practices everywhere, probably using a template for both server & client side HTML creation, never write MySQL queries like you've written (or that I wrote for you). Use MySQLi, or PDO! Think about what would happen if $s_post_id was somehow equal to 5' OR '1'='1 This would just return every comment.. but what if this was done in a DELETE_COMMENT function, and someone wiped your comment table out completely?

Related

Ajax And PHP : Handling Multiple Posts in A Single Page

I am developing a webpage where multiple posts from the Database is shown one by one in a single page much like twitter or facebook.
I need to use Ajax for comments and likes. The comment system should be nested as well.
The problem I am having is each post is having a unique post_id and I need to transfer it through Ajax for inserting the comments into the DB.
The below HTML is inside a PHP for loop for getting the posts from Database. So I have given post_id as every comment element's id to get the unique post comment.
<script>
function addcomment(abc) {
var temp1 = abc;
var post_id = temp1.value; // POST ID
var comment = document.getElementById(post_id).value;
$.ajax({
type: "POST",
url: "addcomment.php",
data: {
post_id:post_id,
comment:comment
},
success: function(response) {
document.getElementsByClassName(post_id).innerHTML = response;
}
});
}
</script>
<div class="comment_section" id="comment_section">
<textarea type="text" id="<?php echo($post_id); ?>" placeholder="comment Here..." value=""></textarea>
<button id="comment_button" value="<?php echo ($post_id); ?>" onclick="return addcomment(this);">Comment</button>
<br>
<span class="<?php echo($post_id); ?>"></span>
</div>
And the addcomment.php looks like this:
<?php
include("connect.php");
$postid = $_POST['post_id'];
$comment = $_POST['comment'];
$sql1 = "INSERT INTO comments (name,comment) VALUES ('$postid','$comment')";
$result = $db->query($sql1);
$sql = "SELECT * FROM comments ORDER BY id DESC LIMIT 0,1";
$result1 = $db->query($sql);
while($row = $result1->fetch_assoc()) {
$post = $row['name'];
$comment_op = $row['comment'];
?>
<?php echo $comment_op; ?>
<br>
<?php echo $post; ?>
<?php } ?>
How can I get the comment when the Comment button clicked and store it in the DB and return the Comment below the comment area using AJAX ?
For display comments on specific post first you create comment section and use
<section id="comments-post_id"></section>
when you successfully add comment via above ajax request code get the response and create comment html and append in your comment section.
$("#comments-post_id").html($response);
make sure you have already create your comment HTML in controller or in ajax file where you get the response.
and for the rendering all post data user inside loop or recursive function to get all comments of your specific post
Need more help feel free and ask :)

How to change files so that when you click on the "load more" button the browser dynamically adds the following entries from the database in the list

How to change files so that when you click on the "load more" button the browser dynamically adds the following entries from the database in the list
index.php
<?php
include('pdo.php');
include('item.php');
include('loadMore.php');
?>
<div id="container">
<?php foreach ($items as $item): ?>
<div class="single-item" data-id="<?= $item->id ?>">
<?= $item->show() ?>
</div>
<?php endforeach; ?>
</div>
<button id="loadMore">Загрузить ещё...</button>
<script src="/jquery-1.11.3.min.js"></script>
<script src="/script.js"></script>
item.php
<?php
class Item
{
public $id;
public $text;
function __construct($id = null, $text = null)
{
$this->id = $id;
$this->text = $text;
}
public function show()
{
return $this->text;
}
}
loadmore.php
<?php
$offset = 0;
$limit = 10;
$statement = $pdo->prepare('SELECT * FROM credit LIMIT ?, ?');
$statement->bindValue(1, $offset, PDO::PARAM_INT);
$statement->bindValue(2, $limit, PDO::PARAM_INT);
$statement->execute();
$data = $statement->fetchAll();
$items = [];
foreach ($data as $item)
{
$items[] = new Item($item['id'], $item['tel']);
}
pdo.php
<?php
$host = '127.0.0.1';
$db = 'test';
$user = 'root';
$pass = '';
$charset = 'utf8';
$dsn = "mysql:host=$host;dbname=$db;charset=$charset";
$opt = [
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
PDO::ATTR_EMULATE_PREPARES => false,
];
$pdo = new PDO($dsn, $user, $pass, $opt);
script.js
function getMoreItems() {
var url = "/loadMore.php";
var data = {
//
};
$.ajax({
url: url,
data: data,
type: 'get',
success: function (res) {
//
},
error: function (XMLHttpRequest, textStatus, errorThrown) {
//
}
});
}
How to change files so that when you click on the "load more" button the browser dynamically adds the following entries from the database in the list
I think 2 hours and I can not understand.
Help.(
I understand your confusion, I believe you're wondering why your php code in index.php doesn't work properly after you call loadMore.php using ajax.
There's one distinction you need to understand to be capable of developing for the web. The difference between server-side and client-side code.
PHP is a server-side programming language, which means that it only executes on the server. Your server returns html, or json, or text, or anything to the browser and once the response arrives at the browser, you can forget about php code.
Javascript on the other hand is a client side programming language (at least in your case) It executes on the browser.
You basically have two options:
To send back some json and loop over it using jQuery, which is the preferable choice, but I fear it requires more work.
Send back html and append it to your page, first create a file called async.php
<?php
include('pdo.php');
include('item.php');
include('loadMore.php');
?>
<?php foreach ($items as $item): ?>
<div class="single-item" data-id="<?= $item->id ?>">
<?= $item->show() ?>
</div>
<?php endforeach; ?>
in your js add to your success callback
$.ajax({
url: url,
data: data,
type: 'get',
success: function (res) {
$('#container').append(res);
},
error: function (XMLHttpRequest, textStatus, errorThrown) {
//
}
});
don't forget var url = "async.php";
First you need to attach the buttons onclick="" attribute with the ajax-method.
<button ... onclick="getMoreItems">...</button>
Second, your loadmore.php need to require_once the files it depends on:
require_once('pdo.php');
require_once('item.php');
Third, separate your logic for querying the database to a function in the pdo.php file you can call with the limits as parameters, i.e.
function getData($offset = 0, $limit = 10){
//logic
}
You should also always try to use require_once or include_once to be sure files aren't loaded several times.
Now you can call the function getData(...) from index.php before the container div to load up the initial data, remove the include to loadmore.php from index.php, and in loadmore.php write the logic to use the parameters sent from the webpage to get the next chunk of data.
The data:... in your ajax needs to pass along the "page" it wants to get, perhaps simply a counter as to how many times you have loaded more. In the loadmore.php script you then just multiply the page by the limit to get the offset.
Return the data as JSON to the ajax, parse the JSON so you can build a new div for each item, then add each div to the container-div using javascript.
Im not going in detail on all topics here, but you at least will know what tutorials to search for on google :)

asynchronous commenting using ajax

I'm trying to create a comment system on my website where the user can comment & see it appear on the page without reloading the page, kind of like how you post a comment on facebook and see it appear right away. I'm having trouble with this however as my implementation shows the comment the user inputs, but then erases the previous comments that were already on the page (as any comments section, I'd want the user to comment and simply add on to the previous comments). Also, when the user comments, the page reloads, and displays the comment in the text box, rather than below the text box where the comments are supposed to be displayed. I've attached the code. Index.php runs the ajax script to perform the asynchronous commenting, and uses the form to get the user input which is dealt with in insert.php. It also prints out the comments stored in a database.
index.php
<script>
$(function() {
$('#submitButton').click(function(event) {
event.preventDefault();
$.ajax({
type: "GET",
url: "insert.php",
data : { field1_name : $('#userInput').val() },
beforeSend: function(){
}
, complete: function(){
}
, success: function(html){
$("#comment_part").html(html);
window.location.reload();
}
});
});
});
</script>
<form id="comment_form" action="insert.php" method="GET">
Comments:
<input type="text" class="text_cmt" name="field1_name" id="userInput"/>
<input type="submit" name="submit" value="submit" id = "submitButton"/>
<input type='hidden' name='parent_id' id='parent_id' value='0'/>
</form>
<div id='comment_part'>
<?php
$link = mysqli_connect('localhost', 'x', '', 'comment_schema');
$query="SELECT COMMENTS FROM csAirComment";
$results = mysqli_query($link,$query);
while ($row = mysqli_fetch_assoc($results)) {
echo '<div class="comment" >';
$output= $row["COMMENTS"];
//protects against cross site scripting
echo htmlspecialchars($output ,ENT_QUOTES,'UTF-8');
echo '</div>';
}
?>
</div>
insert.php
$userInput= $_GET["field1_name"];
if(!empty($userInput)) {
$field1_name = mysqli_real_escape_string($link, $userInput);
$field1_name_array = explode(" ",$field1_name);
foreach($field1_name_array as $element){
$query = "SELECT replaceWord FROM changeWord WHERE badWord = '" . $element . "' ";
$query_link = mysqli_query($link,$query);
if(mysqli_num_rows($query_link)>0){
$row = mysqli_fetch_assoc($query_link);
$goodWord = $row['replaceWord'];
$element= $goodWord;
}
$newComment = $newComment." ".$element;
}
//Escape user inputs for security
$sql = "INSERT INTO csAirComment (COMMENTS) VALUES ('$newComment')";
$result = mysqli_query($link, $sql);
//attempt insert query execution
//header("Location:csair.php");
die();
mysqli_close($link);
}
else{
die('comment is not set or not containing valid value');
}
The insert.php takes in the user input and then inserts it into the database (by first filtering and checking for bad words). Just not sure where I'm going wrong, been stuck on it for a while. Any help would be appreciated.
There are 3 main problems in your code:
You are not returning anything from insert.php via ajax.
You don't need to replace the whole comment_part, just add the new comment to it.
Why are you reloading the page? I thought that the whole purpose of using Ajax was to have a dynamic content.
In your ajax:
$.ajax({
type: "GET",
url: "insert.php",
data : { field1_name : $('#userInput').val() },
beforeSend: function(){
}
, complete: function(){
}
, success: function(html){
//this will add the new comment to the `comment_part` div
$("#comment_part").append(html);
}
});
Within insert.php you need to return the new comment html:
$userInput= $_GET["field1_name"];
if(!empty($userInput)) {
$field1_name = mysqli_real_escape_string($link, $userInput);
$field1_name_array = explode(" ",$field1_name);
foreach($field1_name_array as $element){
$query = "SELECT replaceWord FROM changeWord WHERE badWord = '" . $element . "' ";
$query_link = mysqli_query($link,$query);
if(mysqli_num_rows($query_link)>0){
$row = mysqli_fetch_assoc($query_link);
$goodWord = $row['replaceWord'];
$element= $goodWord;
}
$newComment = $newComment." ".$element;
}
//Escape user inputs for security
$sql = "INSERT INTO csAirComment (COMMENTS) VALUES ('$newComment')";
$result = mysqli_query($link, $sql);
//attempt insert query execution
mysqli_close($link);
//here you need to build your new comment html and return it
return "<div class='comment'>...the new comment html...</div>";
}
else{
die('comment is not set or not containing valid value');
}
Please note that you currently don't have any error handling, so when you return die('comment is not set....') it will be displayed as well as a new comment.
You can return a better structured response using json_encode() but that is outside the scope of this question.
You're using jQuery.html() which is replacing everything in your element with your "html" contents. Try using jQuery.append() instead.

Getting a value from Javascript in PHP [duplicate]

This question already has answers here:
What is the difference between client-side and server-side programming?
(3 answers)
Closed 7 years ago.
I am not very experienced in web programming and am attempting to run a script which updates my database.
<script>
function myFunction() {
var texts = document.getElementById("content").textContent;
alert(texts)
<?php
include_once 'accounts/config.php';
$text = ...;
$tbl_name='enemies'; // Table name
$query = "UPDATE enemies SET text=('$text') WHERE id=1";
$result = mysql_query($query) or die(mysql_error());
?>
}
</script>
I have no idea what to put in the $text section as shown with $text = ...; in order to get the variable texts from above.
EDIT
I have updated my code but the function does not seem to be accessing the PHP file. I am using a button to call the function and I have also tested it so i know the function is being called. My file is called update.php and is in the same directory as this file.
<button onclick="myFunction()">Click This</button>
<script>
function myFunction() {
var texts = document.getElementById("content").textContent;
$.ajax({
url: "update.php",
type: "POST",
data: {texts:texts},
success: function(response){
}
});
}
</script>
you can post your $texts value to other php page using ajax and get the variable on php page using $_POST['texts'] and place update query there and enjoy....
function myFunction() {
var texts = document.getElementById("content").textContent;
$.ajax({
url: 'update.php',
type: "POST",
data: {texts:texts},
success: function(response)
{
}
});
And your php file will be named as update.php
<?php
include_once 'accounts/config.php';
$text =$_POST['texts'];
$tbl_name='enemies'; // Table name
$query = "UPDATE `enemies` SET `text`='".$text."' WHERE `id`=1";
$result = mysql_query($query) or die(mysql_error());
?>
PHP runs on the server and then generates output which is then returned to the client side. You can't have a JavaScript function make a call to inlined PHP since the PHP runs before the JavaScript is ever delivered to the client side.
Instead, what you'd need to do is have your function make an AJAX request to a server-side PHP script that then extracts the data from the request body and then stores it in the database.
PHP: "/yourPhpScript.php"
<?php
include_once 'accounts/config.php';
$text = $_POST['data'];
$tbl_name='enemies'; // Table name
$query = "UPDATE enemies SET text='".$text.'" WHERE id=1";
$result = mysql_query($query) or die(mysql_error());
?>
JavaScript:
function myFunction() {
var texts = document.getElementById("content").textContent;
alert(texts);
// append data as a query string
var params = 'data='+texts;
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
// when server responds, output any response, if applicable
if(http.readyState == 4 && http.status == 200) {
alert(http.responseText);
}
}
// replace with the filename of your PHP script that will do the update.
var url = '/yourPhpScript.php';
xmlhttp.open("POST", url, true);
xmlhttp.send(params);
}
A word of caution: This is not a safe, production-friendly way of updating data in your database. This code is open to SQL injection attacks, which is outside the scope of your question. Please see Bobby Tables: A guide to preventing SQL injection if you are writing code that will go into production.
You are wrong in approach
You should use ajax to post 'texts' value to your php script
https://api.jquery.com/jquery.post/ and create separate php file where you will get data from ajax post and update DB
javascript:
<script>
function myFunction() {
var texts = document.getElementById("content").textContent;
$.ajax({
type: "POST",
url: "update.php",
data: "texsts=" + texts,
success: success
});
}
</script>
update.php
<?php
include_once 'accounts/config.php';
$text = $_POST['texts'];
$tbl_name='enemies'; // Table name
$query = "UPDATE enemies SET text=('$text') WHERE id=1";
$result = mysql_query($query) or die(mysql_error());
?>
i will use PDO if i was you, what you do mysql_query are outdated, if you use my framework https://github.com/parisnakitakejser/PinkCowFramework you can do the following code.
<?php
include('config.php');
$text = $_POST['text'];
$query = PinkCow\Database::prepare("UPDATE enemies SET text = :text WHERE id = 1");
$bindparam = array(
array('text', $text, 'str')
);
PinkCow\Database::exec($query,$bindparam);
$jsonArray = array(
'status' => 200
);
echo json_encode($jsonArray);
?>
place this code in jsonUpdateEnemies.php file and call it width jQuery
<script>
function myFunction(yourText) {
$.post( 'jsonUpdateEnemies.php', {
'text' : yourText
}, function(data)
{
alert('Data updated');
},'json');
}
</script>
its a little more complex then you ask about, but its how i will resolved your problem, :)

PHP is not reloaded automatically after processing

Hi I have a PHP file with data. The value is passed on to another php file which process it successfully. But the first php file does not refresh to update the new result. It have to do it manually. Can any one tell me where I'm wrong or what needs to be done. Please find my code below.
PHP code (1st page, index.php)
function display_tasks_from_table() //Displayes existing tasks from table
{
$conn = open_database_connection();
$sql = 'SELECT id, name FROM todolist';
mysql_select_db('todolist'); //Choosing the db is paramount
$retval = mysql_query( $sql, $conn );
if(! $retval )
{
die('Could not get data: ' . mysql_error());
}
echo "<form class='showexistingtasks' name='showexistingtasks' action='remove_task.php' method='post' >";
while($row = mysql_fetch_assoc($retval))
{
echo "<input class='checkbox' type='checkbox' name='checkboxes{$row['id']}' value='{$row['name']}' onclick='respToChkbox()' >{$row['name']} <img src='images/show_options.gif' /><br>";
}
echo "</form>";
echo "<label id='removeerrormsg'></label>";
close_database_connection($conn);
}
Javascript code which finds the selected value:
var selVal; //global variable
function respToChkbox()
{
var inputElements = document.getElementsByTagName('input'),
input_len = inputElements.length;
for (var i = 0; i<input_len; i++)
{
if (inputElements[i].checked === true)
{
selVal = inputElements[i].value;
}
}
}
jQuery code which passes value to another page (remove_Task.php):
$(document).ready(function() {
$(".checkbox").click(function(){
$.ajax({
type: "POST",
url: "remove_task.php", //This is the current doc
data: {sel:selVal, remsubmit:"1"},
success: function(data){
//alert(selVal);
//console.log(data);
}
});
});
});
PHP code (2nd page, remove_task.php);
session_start();
error_reporting(E_ALL);ini_set('display_errors', 'On');
$task_to_remove = $_POST['sel'];
function remove_from_list() //Removes a selected task from DB
{
$db_connection = open_database_connection();
global $task_to_remove;
mysql_select_db('todolist');
$sql = "DELETE FROM todolist WHERE name = "."'".$task_to_remove."'";
if($task_to_remove!='' || $task_to_remove!=null)
{
mysql_query($sql, $db_connection);
}
close_database_connection($db_connection);
header("Location: index.php");
}
if($task_to_remove != "") {
remove_from_list();
}
The selected value is getting deleted but the display on index.php is not updated automatically. I have to manually refresh to see the updated result. Any help would be appreciated.
By calling header("Location: index.php"); you don't redirect main page. You sent an ajax request - you can think about it as of opening a new page at the background, so this code redirects that page to index.php.
The better way to solve your task is to return status to your success function and remove items which were deleted from the database.
success: function(data){
if(data.success){
//remove deleted items
}
}

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