i want to make a loop in jquery, Ajax and PHP.
my pages are:
shop.php
do_ajax.php
in the shop.php are variable $p_productid is 1 and $j_productid is $p_productid
var j_productid = <?= $p_productid ?>;
now i do j_productid++ so the output from $j_productid is 2
now i'm posting this with ajax to do_ajax.php
in the do_ajax.php are variable $pa_productid is $_POST['$j_productid'];
now i can place this on html, but i want to set this value in too the variable on $p_productid on shop.php
how i need to do this?
there is working a swipe system in this case so only with php it isnt working i need to work with jquery that's why am i doing this on this way. i got an another solution without AJAX but i want that you cant see on the client side the webpage is refreshing.
JQUERY
wipeLeft: function() {
var j_ProductId = <?= $g_ProductId ?>;
var j_Swiped = 1;
if (j_ProductId < <?= $l_LastProduct ?>){
j_ProductId++
//document.swiping.productid.value = j_ProductId;
//document.swiping.submit();
$.ajax({
url: 'do_ajax.php',
type: 'POST',
data: { swipe : j_Swiped,
productid : j_ProductId},
success: function (data) {
$('.product').html(data);
}
});
}
}
do_ajax.php
if(!empty($_POST['swipe'])){
$l_ProductId = $_POST['productid'];
echo $l_ProductId;
}
You need to understand that the JavaScript (even if generated dynamically by PHP) is not running the same time that PHP is running. Your workflow will be something like this:
PHP script (shop.php) is invoked
PHP script generates output, HTML and JS mixed.
These are all in server side until the web server sends the output to client (browser)
In browser HTML displays and JS runs with starting values that you generated previously by PHP. But in this time, PHP has been finished, not running anymore. PHP variables are not alive anymore.
JS interacts with the user in browser, we can say it's running continuously.
Triggered by an action (swipe) JS sends an (ajax) request from client side to server side. This request transfers the new value to server side, and invokes another PHP script (do_ajax.php). You do whatever you want with the new value (process it and or store it) in server side. You need to understand that you are in a completely disjunct scope in PHP than in your first PHP script. (distinct in time too)
If you want to be sure that, in case of a page reload, the (product ID) value will be the updated value, you need to store it somewhere (user session, key-value store, database, or any persistent) when you get it in server side (so in do_ajax.php) and later load this value in the beginning of your shop.php script ...which will pass it to the JS, and so on. The workflow starts again.
Related
Is it possible to set PHP session variables using Javascript?
In JavaScript:
jQuery('#div_session_write').load('session_write.php?session_name=new_value');
In session_write.php file:
<?
session_start();
if (isset($_GET['session_name'])) {$_SESSION['session_name'] = $_GET['session_name'];}
?>
In HTML:
<div id='div_session_write'> </div>
The session is stored server-side so you cannot add values to it from JavaScript. All that you get client-side is the session cookie which contains an id. One possibility would be to send an AJAX request to a server-side script which would set the session variable. Example with jQuery's .post() method:
$.post('/setsessionvariable.php', { name: 'value' });
You should, of course, be cautious about exposing such script.
If you want to allow client-side manipulation of persistent data, then it's best to just use cookies. That's what cookies were designed for.
or by pure js, see also on StackOverflow :
JavaScript post request like a form submit
BUT WHY try to set $_session with js? any JS variable can be modified by a player with
some 3rd party tools (firebug), thus any player can mod the $_session[]! And PHP cant give js any secret codes (or even [rolling] encrypted) to return, it is all visible. Jquery or AJAX can't help, it's all js in the end.
This happens in online game design a lot. (Maybe a bit of Game Theory? forgive me, I have a masters and love to put theory to use :) ) Like in crimegameonline.com, I
initialize a minigame puzzle with PHP, saving the initial board in $_SESSION['foo'].
Then, I use php to [make html that] shows the initial puzzle start. Then, js takes over, watching buttons and modding element xy's as players make moves. I DONT want to play client-server (like WOW) and ask the server 'hey, my player want's to move to xy, what should I do?'. It's a lot of bandwidth, I don't want the server that involved.
And I can just send POSTs each time the player makes an error (or dies). The player can block outgoing POSTs (and alter local JS vars to make it forget the out count) or simply modify outgoing POST data. YES, people will do this, especially if real money is involved.
If the game is small, you could send post updates EACH move (button click), 1-way, with post vars of the last TWO moves. Then, the server sanity checks last and cats new in a $_SESSION['allMoves']. If the game is massive, you could just send a 'halfway' update of all preceeding moves, and see if it matches in the final update's list.
Then, after a js thinks we have a win, add or mod a button to change pages:
document.getElementById('but1').onclick=Function("leave()");
...
function leave() {
var line='crimegameonline-p9b.php';
top.location.href=line;
}
Then the new page's PHP looks at $_SESSION['init'] and plays thru each of the
$_SESSION['allMoves'] to see if it is really a winner. The server (PHP) must decide if it is really a winner, not the client (js).
You can't directly manipulate a session value from Javascript - they only exist on the server.
You could let your Javascript get and set values in the session by using AJAX calls though.
See also
Javascript and session variables
jQuery click event to change php session variable
One simple way to set session variable is by sending request to another PHP file. Here no need to use Jquery or any other library.
Consider I have index.php file where I am creating SESSION variable (say $_SESSION['v']=0) if SESSION is not created otherwise I will load other file.
Code is like this:
session_start();
if(!isset($_SESSION['v']))
{
$_SESSION['v']=0;
}
else
{
header("Location:connect.php");
}
Now in count.html I want to set this session variable to 1.
Content in count.html
function doneHandler(result) {
window.location="setSession.php";
}
In count.html javascript part, send a request to another PHP file (say setSession.php) where i can have access to session variable.
So in setSession.php will write
session_start();
$_SESSION['v']=1;
header('Location:index.php');
Not possible. Because JavaScript is client-side and session is server-side. To do anything related to a PHP session, you have to go to the server.
be careful when doing this, as it is a security risk. attackers could just repeatedly inject data into session variables, which is data stored on the server. this opens you to someone overloading your server with junk session data.
here's an example of code that you wouldn't want to do..
<input type="hidden" value="..." name="putIntoSession">
..
<?php
$_SESSION["somekey"] = $_POST["putIntoSession"]
?>
Now an attacker can just change the value of putIntoSession and submit the form a billion times. Boom!
If you take the approach of creating an AJAX service to do this, you'll want to make sure you enforce security to make sure repeated requests can't be made, that you're truncating the received value, and doing some basic data validation.
I solved this question using Ajax. What I do is make an ajax call to a PHP page where the value that passes will be saved in session.
The example that I am going to show you, what I do is that when you change the value of the number of items to show in a datatable, that value is saved in session.
$('#table-campus').on( 'length.dt', function ( e, settings, len ) {
$.ajax ({
data: {"numElems": len},
url: '../../Utiles/GuardarNumElems.php',
type: 'post'
});
});
And the GuardarNumElems.php is as following:
<?php
session_start();
if(isset ($_POST['numElems'] )){
$numElems = $_POST['numElems'];
$_SESSION['elems_table'] = $numElems;
}else{
$_SESSION['elems_table'] = 25;
}
?>
I am trying to save a variable for counting the views of my personal website, I dont need to use php because its literally a viewcount. I know how to retrieve the count from the server using $.post, but how would I retrieve it (Edit: In the simplest way possible.)?
The website I'm trying to do it with is http://artsicleprojects.com/
Thanks in advance!
You will need PHP for this question, because it is dealing with server-side actions. First, you need to make a server-side script to increment the text file's number. Then, you will need to make a client-side script to make a request to the server. This script increments a number in the text file every time the request is made. Anyway, here's how I would do it (Note: this code is un-tested):
PHP:
<?php
/*Reads and collects current count.*/
$rfile = fopen("views.txt", "r") or die("Unable to open file!");
$count = fread($rfile,filesize("views.txt"));
fclose($rfile);
/*Increments the count.*/
$wfile = fopen("views.txt", "w");
$ncount = $count + 1;
fwrite($wfile, $ncount);
fclose($wfile);
?>
Note on code: for this code to work correctly, you may need a text file already made (views.txt), in the same directory as the PHP script, with a single "0" written in it.
JavaScript (with jQuery):
$.post("phpscript.php", function(data, status){
console.log(status);
});
This also is supposed to be in the same directory as the script to work.
At page 0 inputs are entered. Then Page 0 is submitted to php page 1
At php page 1 i calculate $Ama;
At php page 2 (required by page1), i need to ask one more verification check.
Hence in php page 2 :
if($Ama ==0 )
{
echo '<script>
var a = confirm("Ama is Zero. Are you sure?";
if(a){
//Set A SESSION VARIABLE
}
</script>';
}
How do i append to this a $_SESSION['Accepted']=0 where marked in Code.? I am having a problem with syntax to append this.
Since this confirm() check is done on client side, you can't run PHP code, so you will have to use AJAX to send request to server to append whatever values you want to the session.
There are many tutorials available, here is a simple way to do AJAX calls using jQuery http://api.jquery.com/jquery.ajax/
You can't manipulate a session value from Javascript, they only exist on the server.
<?php
// Connect to database server
mysql_connect("192.168.1.101/phpmyadmin/", "root", "praticas") or die (mysql_error ());
// Select database
mysql_select_db("logs_history") or die(mysql_error());
//---> at this point, I want yo pull a VALUE from a column called potencia_ativa and insert in
// the code JS below
mysql_query($strSQL);
// Close the database connection
mysql_close();
?>
//JS code-------------------------------------------------------------------------------------------
<div id="graphHolder" style="height:75%;width:100%"></div>
<script type="text/javascript">
setInterval(
function() {
var d1 = [];
for (var i = 0; i < parseInt(document.getElementById('number').value,10); i += 0.5) {
d1.push([ //----------> pull the value from the php/DB as a FLOAT
]);
}
$.plot("#graphHolder", [{
label: "Label",
data: d1,
lines: { show: true, fill: true }
}
]);
}, 1000);
</script>
Remember, PHP executes on the server and GENERATES the page that runs the Javascript on the client. Putting a value from PHP into the JS code is as simple as:
<script>
var foo = <?php echo json_encode('bar'); ?>;
</script>
If you need to send the PHP data over AFTER the page was generated and already send to the client, then you need to have the client execute an AJAX request to fetch that data from the server. Once PHP has shoved the page out the door, it's basically done and can't "reach out" to the client to do updates on its own.
Also: Note the use of json_encode(). You should NEVER dump output from PHP directly into a Javascript context without it. Anything else puts you at risk of generating JS syntax errors, which will kill the entire JS code block.
Why are you using Interval? Are you trying to update the displaying page data/value automatically after some time passed? That won't work, because if anything changes in database, It won't change in the displaying page, unless you use AJAX to call your php script and return some values, and then, change in the displaying page.
To get a value from PHP script to JAVASCRIPT, you just need to use the php clausule;
var test = <?php echo $variable; ?>
// echo for strings, ints, floats.
// print_r for arrays.
Of course, if your PHP script already injected the data into the page/the data is in the same page you're using JAVASCRIPT, assuming that you have already fetched the data, handled it and etc.
Hi I'm trying to learn PHP and javascript, therefore I tried to do an exercise about passing data but I didn't understand the js function and currently unable to do anything.
Here is the code
php-code.php
$v1=$_GET['v1'];
$v2=$_GET['v2'];
$v3=$_GET['v3'];
//Some operations about them
echo $output;
my-js.js
var v1 = $('#v1 option:selected').val();
var v2 = $('#v2 option:selected').val();
var v3 = $('#v3 option:selected').val();
//This is where I want to pass these variables to my php file and get the output
//But i don't know how
js-execute.php
//this is where my js gets the variables at first
PHP is a server-side language while JavaScript is a client-side one. This means that PHP will be executed when someone requests a page, but the browser will only get the result of the PHP code. On the other hand, JavaScript is sent to the browser and the browser will execute it at the appropriate time (when the page loads or when an event happens). That's why if you look at the source code of a page, you will be able to see the JavaScript code, but never the PHP code.
If you want to pass values from JavaScript to PHP, you will need to make a remote call to a PHP file. PHP isn't like JavaScript – once it's done running its code, it won't be able to respond to anything without a reload of the page.
The easiest way to send something to a PHP file and fetching the result with JavaScript can probably be achieved with JQuery. It has a function $.get which will fetch a given URL. Just be sure to properly validate the input on the server side – never trust user input.
JavaScript (using JQuery to send v1, v2 and v3 to page.php)
function requestPage(v1, v2, v3) {
$.get('page.php', {'v1':v1, 'v2':v2, 'v3':v3}, function(data) {
alert(data);
});
}
PHP (a trivial example)
// Be sure to properly validate input!
if(isset($_GET['v1']) && is_scalar($_GET['v1'])) {
echo strrev($_GET['v1']);
}