Develop Reference

Updating an input field with PHP vale in JavaScript

I want to update the value of an input field when I receive some information from an api. I tried using:
$('#txtFirstName').val($_SESSION['jUser']['first_name']);
But an error occurs due to the PHP not being able to run in a js file. How can I make this update otherwise? Is there a way in js to update the entire form and input fields without submitting?
I can't reload the entire window, because it will eliminate other information that the user of the website has put in.

1) put value into #txtFirstName from php script
// script.php code
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
echo $_SESSION['jUser']['first_name'];
}
// javascript code
function func(){
$.ajax({
type: "POST",
url: "script.php",
success: function (response) {
$('#txtFirstName').val(response);
},
error: function (e) {
console.log("ERROR : ", e);
}
});
}
2) put value into $_SESSION['jUser']['first_name'] from javascript
// javascript code
function func(){
var your_value = "some_value";
$.ajax({
type: "POST",
url: "script.php",
data: { va: your_value },
success: function (response) {
console.log("value setted to session successfully");
},
error: function (e) {
console.log("ERROR : ", e);
}
});
}
// script.php code
if ($_SERVER['REQUEST_METHOD'] === 'POST' && $_POST['va'] !='') {
$_SESSION['jUser']['first_name'] = $_POST['va'];
echo "ok";
}

Why don't you just echo the value from php script and make an AJAX request from javascript to get the value ? This should be the recommended approach.
However, it can also be accomplished with the approach you've taken:
let first_name = <?php echo $_SESSION['jUser']['first_name']; ?>:
$('#txtFirstName').val(first_name);
For further reading, you can visit How do I embed PHP code in JavaScript?
.

jquery.ajax to PHP fails when I use ECHO in my PHP

this is the 1st time I try to use AJAX - my website needs to call a PHP during runtime when the user leaves a specific form field (VIN). I pass the value of this field to a PHP function for validation and processing. Then PHP should return 3 values for 3 different form fields.
This is my problem: I won't get the 3 values back into my javascript.
Each time when I use ECHO json_encode in my php the AJAX call crashes and the console shows "VM7190:1 Uncaught SyntaxError: Unexpected token Y in JSON at position 0(…)".
If I put any other simple ECHO in my PHP the AJAX call would return with an error.
If I remove each ECHO from my PHP the AJAX call returns as success but the returning data is NULL.
It would be so great if I could get a solution for this problem here.
If anybody would like to test the site - this is the url: mycarbio
Thank you very much.
This is my AJAX call:
function decode_my_vin(myvin) {
alert("in decode_my_vin");
dataoneID = '123';
dataoneKEY = 'xyz';
jQuery.ajax(
{
cache: false,
type: 'POST',
url: '/wp-content/themes/Impreza-child/vin-decoder.php',
dataType:'json',
data: {
'value1_VIN': myvin,
'value2_ID': dataoneID,
'value3_KEY': dataoneKEY,
'value4_Year': ' ',
'value5_Make': ' ',
'value6_Model': ' '
},
// async: false,
success: function(response) {
var obj = jQuery.parseJSON(response);
alert("success returned: " + obj);
document.getElementById("fld_7290902_1").value = "2015";
document.getElementById("fld_1595243_1").value = "Ford";
document.getElementById("fld_7532728_1").value = "Focus";
return;
},
error: function() { alert("error in der jquery"); }
});
}
And this is my PHP
<?php
header('Content-Type: application/json');
$resultYear = '2010';
$resultMake = 'Ford';
$resultModel = 'Focus';
$vinResult = array("Year: ", $resultYear, "Make: ", $resultMake, "Model: ", $resultModel);
echo json_encode($vinResult);
?>

This may not be your only problem, but you should try using an associative array when rendering the JSON:
$vinResult = array(
'Year' => $resultYear,
'Make' => $resultMake,
'Model' => $resultModel
);
Currently you are combining your property names and values.

Delete post using $.ajax

I am new to $.ajax and don't know so much and i have following button to delete user post by article ID
<button type="button" onclick="submitdata();">Delete</button>
When click this button then following $.ajax process running.
<script>
var post_id="<?php echo $userIdRow['post_id']; ?>";
var datastring='post_id='+post_id;
function submitdata() {
$.ajax({
type:"POST",
url:"delete.php",
data:datastring,
cache:false,
success:function(html) {
alert(html);
}
});
return false;
}
</script>
And delete.php is
<?php
// connect to the database
include 'conn.php';
$dbClass = new Database();
// confirm that the 'post_id' variable has been set
if (isset($_GET['post_id']) && is_numeric($_GET['post_id'])) {
// get the 'post_id' variable from the URL
$post_id = $_GET['post_id'];
// delete record from database
if ($userPostsQuery = $dbClass::Connect()->prepare("DELETE FROM user_posts WHERE post_id = :post_id")) {
$userPostsQuery->bindValue(":post_id", $post_id, PDO::PARAM_INT);
$userPostsQuery->execute();
$userPostsQuery->close();
echo "Deleted success";
} else {
echo "ERROR: could not prepare SQL statement.";
}
}
?>
This code not working post not deleted. Please how do I do?

You likely want to not only match the "GET" you use in your PHP but also add the ID to the button
<button class="del" type="button"
data-id="<?php echo $userIdRow['post_id']; ?>">Delete</button>
using $.get which matches your PHP OR use $.ajax({ "type":"DELETE"
$(function() {
$(".del").on("click", function() {
$.get("delete.php",{"post_id":$(this).data("id")},
function(html) {
alert(html);
}
);
});
});
NOTE: Please clean the var
Do htmlspecialchars and mysql_real_escape_string keep my PHP code safe from injection?
Using ajax DELETE with error handling
$(function() {
$(".del").on("click", function() {
$.ajax({
url: "delete.php",
method: "DELETE", // use "GET" if server does not handle DELETE
data: { "post_id": $(this).data("id") },
dataType: "html"
}).done(function( msg ) {
$( "#log" ).html( msg );
}).fail(function( jqXHR, textStatus ) {
alert( "Request failed: " + textStatus );
});
});
});
In the PHP you can do
if ($_SERVER['REQUEST_METHOD'] === 'DELETE') {
$id = $_REQUEST["post_id"] ....
}

since you're sending a post request with ajax so you should use a $_POST iin your script and not a $_GET
here is how it sould be
<?php
// connect to the database
include 'conn.php';
$dbClass = new Database();
// confirm that the 'post_id' variable has been set
if (isset($_POST['post_id']) && is_numeric($_POST['post_id'])) {
// get the 'post_id' variable from the URL
$post_id = $_POST['post_id'];
// delete record from database
if ($userPostsQuery = $dbClass::Connect()->prepare("DELETE FROM user_posts WHERE post_id = :post_id")) {
$userPostsQuery->bindValue(":post_id", $post_id, PDO::PARAM_INT);
$userPostsQuery->execute();
$userPostsQuery->close();
echo "Deleted success";
} else {
echo "ERROR: could not prepare SQL statement.";
}
}
?>
for the JS code
<script>
var post_id="<?php echo $userIdRow['post_id']; ?>";
function submitdata() {
$.ajax({
type:"POST",
url:"delete.php",
data:{"post_id":post_id},
cache:false,
success:function(html) {
alert(html);
}
});
return false;
}
</script>
here i've supposed thqt the give you the real id post you're looking for !!

The reason is pretty simple. You should change your request type to GET/DELETE instead of POST. In PHP you expect GET request but in AJAX you send POST request
Change:
type:"POST",
url:"delete.php",
data:datastring,
to
type:"DELETE",
url:"delete.php?" + datastring,
in PHP
if ($_SERVER['REQUEST_METHOD'] === 'DELETE' && !empty($_REQUEST["post_id") {
$id = $_REQUEST["post_id"];
// perform delete
}
DELETE is actually the only valid method to delete objects. POST should create an object and GET should retrieve it. It may be confusing at first time but it's good practicet specially used in REST APIs. The other one would be UNLINK if you wanted to remove relationship between objects.

Follow #roberts advise and also:
You should have a way to handle errors eg.
to your ajax code add this:
error:function(e){
alert(e.statusText)// if you like alerts
console.log(e.statusText)// If you like console
}
You should also check your error logs. Assuming you use apache2 and linux
execute this in terminal:
tail -f /var/log/apache2/error.log
This gives you a very elaborate way to code. You also eliminate the problem of trial and error.

AJAX take data from POST with PHP

i have a little problem with my script.
I want to give data to a php file with AJAX (POST).
I dont get any errors, but the php file doesn't show a change after AJAX "runs" it.
Here is my jquery / js code:
(#changeRank is a select box, I want to pass the value of the selected )
$(function(){
$("#changeRank").change(function() {
var rankId = this.value;
//alert(rankId);
//$.ajax({url: "/profile/parts/changeRank.php", type: "post", data: {"mapza": mapza}});
//$("body").load("/lib/tools/popups/content/ban.php");
$.ajax({
type: "POST",
async: true,
url: '/profile/parts/changeRank.php',
data: { 'direction': 'up' },
success: function (msg)
{ alert('success') },
error: function (err)
{ alert(err.responseText)}
});
});
});
PHP:
require_once('head.php');
require_once('../../lib/permissions.php');
session_start();
$user = "test";
if($_SESSION["user"] != $user && checkPermission("staff.fakeLogin", $_SESSION["user"], $mhost, $muser, $mpass, $mdb))
$_SESSION["user"] = $user;
header('Location:/user/'.$user);
die();
When i run the script, javascript comes up with an alert "success" which means to me, that there aren't any problems.
I know, the post request for my data is missing, but this is only a test, so im planning to add this later...
I hope, you can help me,
Greets :)

$(function(){
$("#changeRank").change(function() {
var rankId = this.value;
//alert(rankId);
//$.ajax({url: "/profile/parts/changeRank.php", type: "post", data: {"mapza": mapza}});
//$("body").load("/lib/tools/popups/content/ban.php");
$.ajax({
type: "POST",
async: true,
url: '/profile/parts/changeRank.php',
data: { 'direction': 'up' },
success: function (msg)
{ alert('success: ' + JSON.stringify(msg)) },
error: function (err)
{ alert(err.responseText)}
});
});
});
require_once('head.php');
require_once('../../lib/permissions.php');
session_start();
$user = "test";
if($_SESSION["user"] != $user && checkPermission("staff.fakeLogin", $_SESSION["user"], $mhost, $muser, $mpass, $mdb))
$_SESSION["user"] = $user;
echo json_encode($user);
This sample code will let echo the username back to the page. The alert should show this.

well your js is fine, but because you're not actually echoing out anything to your php script, you wont see any changes except your success alert. maybe var_dump your post variable to check if your data was passed from your js file correctly...

Just return 0 or 1 from your php like this
Your PHP :
if($_SESSION["user"] != $user && checkPermission("staff.fakeLogin", $_SESSION["user"], $mhost, $muser, $mpass, $mdb))
{
$_SESSION["user"] = $user;
echo '1'; // success case
}
else
{
echo '0'; // failure case
}
Then in your script
success: function (msg)
if(msg==1)
{
window.location = "home.php"; // or your success action
}
else
{
alert('error);
}
So that you can get what you expect

If you want to see a result, in the current page, using data from your PHP then you need to do two things:
Actually send some from the PHP. Your current PHP redirects to another URL which might send data. You could use that or remove the Location header and echo some content out instead.
Write some JavaScript that does something with that data. The data will be put into the first argument of the success function (which you have named msg). If you want that data to appear in the page, then you have to put it somewhere in the page (e.g. with $('body').text(msg).

ajax request all return error 500

When ever I am doing an ajax request with jquery I always get an error 500 return,
I am posting to the following URL
http://localhost/domain/index.php/my_profile/interests_music
using this javascript,
$("#add").click(function(e){
//set some process variables, we need to get the forms action,
//and any post data it is sending appending isAjax into the params
//gives us a point in the controller to gracefully check for ajax.
var action = $(this).parent('form').attr('action');
var formData = $(this).parent('form').serialize()+"&isAjax=1";
$.ajax({
type: "POST",
url: action,
data: formData
}).done(function( msg ) {
alert( "Data Saved: " + msg );
});
e.preventDefault();
});
The params that are being sent are,
music=Savage Garden&isAjax=1
And the PHP method the ajax is requesting looks like this,
public function interests_music()
{
if($this->input->post('music'))
{
$this->rest->initialize(array('server' => 'https://www.googleapis.com/freebase/v1'));
$response = $this->rest->get('mqlread?query={"type":"/music/artist","name":"' . urlencode($this->input->post('music')) . '","id":[]}');
$data['image'] = 'https://usercontent.googleapis.com/freebase/v1/image'.$response->result->id[0].'?mode=fillcrop&maxwidth=80&maxheight=80';
$data['category'] = 'music';
$data['user_id'] = $this->session->userdata('id');
$data['name'] = $this->input->post('music', TRUE);
$this->profile_model->add_interest($data);
Events::trigger('interests_music');
Events::trigger('badge_stagediver');
if($this->input->post('isAjax') == 1)
{
echo json_endcode($data);
$this->_buttons();
}
redirect('my_profile/interests');
}
else
{
show_404();
}
}
Am I missing something, is this a common problem?

Well for one there's a typo in your PHP which could be what your server is choking on: echo json_endcode($data); should be echo json_encode($data);. Aside from that there could be other issues with your HTTP server. What server are you using? A good practice is to find the server error log and PHP error log and use tail -f or some other method of monitoring the logs which should give you more information when you have 505s.