I am trying to write code to bring session variables from one php to another without refreshing. I tried to follow the example I found on web as below. It seems to bring the value successfully when loading the ajax page. However, the session variable created seems unable to be preserved even I use the session_start() command. Instead of loading the data, it shows the following error message:
Notice: Undefined index: numSum in C:\xampp\htdocs\test\update.php on line 5
I'd appreciate it if anyone can advise what to do with the code in order to get it right.
index.php
<html>
<?php
session_start();
?>
<script src="http://code.jquery.com/jquery-1.10.1.min.js"></script>
<script type="text/javascript">
j_TOC = [1,2,3,4,5];
$.ajax({
method: "POST",
url: "update.php",
data: { numSum: j_TOC}
})
.done(function( msg ) {
alert( "Data Saved: " + msg );
});
</script>
</html>
update.php
<html>
<?php
session_start();
session_save_path('/session_data/');
$_SESSION['numSum1'] = $_POST['numSum'];
?>
<script type="text/javascript">
function atest() {
var id_toc = <?php echo json_encode($_SESSION['numSum1']); ?>;
window.alert(id_toc);
{
</script>
<input type="button" id="clickme" onclick="atest()" value="update session"></>
</html>
There are few issues with your code, such as:
Normal code flow: When you first visit index.php, it will trigger the AJAX request, and will subsequently set the session variable; so that when you visit update.php page, you'll get the desired result.
Your code flow: Having said the above point, if you directly visit the update.php page without visiting index.php in the first place, you'll get this error,
Notice: Undefined index: numSum in ...
And that's because $_POST['numSum'] is not set, in fact, the entire superglobal $_POST array is empty.
So the solution is this,
Wrap this statement $_SESSION['numSum1'] = $_POST['numSum']; inside an if block, like this:
if(!isset($_SESSION['numSum1']) || empty($_SESSION['numSum1'])){
$_SESSION['numSum1'] = isset($_POST['numSum']) ? $_POST['numSum'] : array();
}
There's also a small syntax error in your code,
function atest() {
var id_toc = <?php echo json_encode($_SESSION['numSum1']); ?>;
window.alert(id_toc);
{ <============ See here, it should be }
You forgot to add a closing parentheses }
Finally, from the documentation,
... Session data path. If specified, the path to which data is saved will be changed. session_save_path() needs to be called before session_start() for that purpose.
Edited:
Change your if block in the following way,
if(!isset($_SESSION['numSum1']) || empty($_SESSION['numSum1']) || (isset($_POST['numSum']) && $_POST['numSum'] != $_SESSION['numSum1'])){
$_SESSION['numSum1'] = isset($_POST['numSum']) ? $_POST['numSum'] : array();
}
Also, learn about comparison operators in PHP, especially about ternary operator. The question mark(?:) you're talking about is related to ternary operator. Here are the necessary references,
http://php.net/manual/en/language.operators.comparison.php (Comparison operators)
http://php.net/manual/en/language.operators.comparison.php#language.operators.comparison.ternary (Ternary operator)
session_save_path() should be called prior to session_start(), and if you're going to use it, use it both scripts where you use session_start()
update.php should just return a string for alert(). When you load that page directly, $_POST is empty, so that is the error you're seeing.
Related
I know there a fair few entries on SO and the web on this however I just can't get to work - any help would be appreciated.
So i have an array in Javascript which I'm trying to pass on to PHP.
I've got a little JS function to first POST it, so:
function sendToPHP() {
$.post("index.php", { "variable": toSearchArray });
}
Then down the page, I have the PHP:
<?php
$myval = $_POST['variable'];
print_r ($myval);
?>
*The prints just there for me to check.
Any ideas - fyi I'm using MAMP so its localhost:8888/index.php. Could this be causing issues in that the URL is not correct?
Thanks.
You have a misunderstanding about how ajax works. Although jquery makes it easy, it is still not automatic. You should just find a tutorial about ajax with jquery, but if you want to just send an array to php and see the output on screen, something like this would work:
index.php
<html>
<head>
<title>Test</title>
<script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
//attach to the button a click event
$('#btn').click(function(){
//get the value from the textbox
var txt=$('#txt').val();
//if txt is blank, alert an error
if(txt == ''){
alert("Enter some text");
} else {
//send txt to the server
//notice the function at the end. this gets called after the data has been sent
$.post('catcher.php', {'text':txt}, function(data){
//now data is an object, so put the message in the div
$('#response').text(data.message);
}, 'json');
}
});
});
</script>
</head>
<body>
<input type="text" id="txt">
<input type="button" id="btn">
<pre id="response" style="overflow:auto;width:800px;height:600px;margin:0 auto;border:1px solid black;"> </pre>
</body>
</html>
catcher.php:
<?php
//if something was posted
if(!empty($_POST)){
//start an output var
$output = array();
//do any processing here.
$output['message'] = "Success!";
//send the output back to the client
echo json_encode($output);
}
It is better to use 2 files, one for the user to load that initiates the ajax call and one page to handle the ajax call. Sending an array works the same, just replace getting the textbox value with sending an array.
Instead of declaring variable toSearchArray as array. consider it an javascript object.
var toSearchArray = {}.
This is what happens when you open your page (index.php)
A GET request is issued to index.php and the content is returned. There are no values in the $_POST array so your print_r() line does nothing.
Javascript is executed that sends a POST request to index.php via AJAX. Note that this is an entirely new request, separate to the original GET. The $_POST array will be populated on this request however the response is discarded.
Hopefully this will illustrate what you can do.
ajax.php
<?php
header("content-type: application/json");
exit(json_encode($_POST));
index.php
<script>
const toSearchArray = ['some', 'array', 'with', 'values'];
$.post('ajax.php', {
variable: toSearchArray
}).done(data => {
console.log(data) // here you will see the result of the ajax.php script
})
</script>
Well I don't think thats the right way to do it when it comes to arrays, see you need to use JSON encode in javascript then JSON decode in php
Refer to this question Pass Javascript Array -> PHP
I know there a fair few entries on SO and the web on this however I just can't get to work - any help would be appreciated.
So i have an array in Javascript which I'm trying to pass on to PHP.
I've got a little JS function to first POST it, so:
function sendToPHP() {
$.post("index.php", { "variable": toSearchArray });
}
Then down the page, I have the PHP:
<?php
$myval = $_POST['variable'];
print_r ($myval);
?>
*The prints just there for me to check.
Any ideas - fyi I'm using MAMP so its localhost:8888/index.php. Could this be causing issues in that the URL is not correct?
Thanks.
You have a misunderstanding about how ajax works. Although jquery makes it easy, it is still not automatic. You should just find a tutorial about ajax with jquery, but if you want to just send an array to php and see the output on screen, something like this would work:
index.php
<html>
<head>
<title>Test</title>
<script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
//attach to the button a click event
$('#btn').click(function(){
//get the value from the textbox
var txt=$('#txt').val();
//if txt is blank, alert an error
if(txt == ''){
alert("Enter some text");
} else {
//send txt to the server
//notice the function at the end. this gets called after the data has been sent
$.post('catcher.php', {'text':txt}, function(data){
//now data is an object, so put the message in the div
$('#response').text(data.message);
}, 'json');
}
});
});
</script>
</head>
<body>
<input type="text" id="txt">
<input type="button" id="btn">
<pre id="response" style="overflow:auto;width:800px;height:600px;margin:0 auto;border:1px solid black;"> </pre>
</body>
</html>
catcher.php:
<?php
//if something was posted
if(!empty($_POST)){
//start an output var
$output = array();
//do any processing here.
$output['message'] = "Success!";
//send the output back to the client
echo json_encode($output);
}
It is better to use 2 files, one for the user to load that initiates the ajax call and one page to handle the ajax call. Sending an array works the same, just replace getting the textbox value with sending an array.
Instead of declaring variable toSearchArray as array. consider it an javascript object.
var toSearchArray = {}.
This is what happens when you open your page (index.php)
A GET request is issued to index.php and the content is returned. There are no values in the $_POST array so your print_r() line does nothing.
Javascript is executed that sends a POST request to index.php via AJAX. Note that this is an entirely new request, separate to the original GET. The $_POST array will be populated on this request however the response is discarded.
Hopefully this will illustrate what you can do.
ajax.php
<?php
header("content-type: application/json");
exit(json_encode($_POST));
index.php
<script>
const toSearchArray = ['some', 'array', 'with', 'values'];
$.post('ajax.php', {
variable: toSearchArray
}).done(data => {
console.log(data) // here you will see the result of the ajax.php script
})
</script>
Well I don't think thats the right way to do it when it comes to arrays, see you need to use JSON encode in javascript then JSON decode in php
Refer to this question Pass Javascript Array -> PHP
HTML
<div pid="14" class="buybutton">Buy</div>
Javascript
<script>
$(document).ready(function() {
$(".buybutton").click(function(){
console.log("Clicked Button");
var pid = $(this).attr("pid");
console.log(pid,"= Product ID");
$.post("/redirecttoproduct.php", {"pidofproduct": pid});
});
});
</script>
Console:
Clicked Button
14 = Product ID
redirecttoproduct.php
<?php
session_start();
$_SESSION['redirectproductpid'] = $_POST['pidofproduct'];
?>
Trying to echo SESSION, nothing shows up
<?php
$productpid = $_SESSION['redirectproductpid'];
echo $productpid;
?>
Nothing shows up - Any ideas?
Did you missed the session_start(); in this page? session_start() is necessary when you use $_SESSION.
<?php
session_start();
$productpid = $_SESSION['redirectproductpid'];
echo $productpid;
?>
I suggest do a callback function first to check if the post request is successfully submitted, one of the reason your $_SESSION variable doesn't return any value is because your js code doesn't post any values to it at all, in result no data is being assigned to your $_SESSION var, ie:
$.post("/redirecttoproduct.php", {"pidofproduct": pid})
.done(function() {alert( "success" );})
.fail(function() {alert( "error" );});
And it would be more convenient if you could supply an absolute path to your $.post request like your website's dir url ie: $.post("//yourwebsite.com/redirecttoproduct.php") with this relative path errors can be significantly avoided, and make sure your not submitting invalid values that would not pass your XSS filters (if there are any), hope this helps, cheers!
I know there a fair few entries on SO and the web on this however I just can't get to work - any help would be appreciated.
So i have an array in Javascript which I'm trying to pass on to PHP.
I've got a little JS function to first POST it, so:
function sendToPHP() {
$.post("index.php", { "variable": toSearchArray });
}
Then down the page, I have the PHP:
<?php
$myval = $_POST['variable'];
print_r ($myval);
?>
*The prints just there for me to check.
Any ideas - fyi I'm using MAMP so its localhost:8888/index.php. Could this be causing issues in that the URL is not correct?
Thanks.
You have a misunderstanding about how ajax works. Although jquery makes it easy, it is still not automatic. You should just find a tutorial about ajax with jquery, but if you want to just send an array to php and see the output on screen, something like this would work:
index.php
<html>
<head>
<title>Test</title>
<script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
//attach to the button a click event
$('#btn').click(function(){
//get the value from the textbox
var txt=$('#txt').val();
//if txt is blank, alert an error
if(txt == ''){
alert("Enter some text");
} else {
//send txt to the server
//notice the function at the end. this gets called after the data has been sent
$.post('catcher.php', {'text':txt}, function(data){
//now data is an object, so put the message in the div
$('#response').text(data.message);
}, 'json');
}
});
});
</script>
</head>
<body>
<input type="text" id="txt">
<input type="button" id="btn">
<pre id="response" style="overflow:auto;width:800px;height:600px;margin:0 auto;border:1px solid black;"> </pre>
</body>
</html>
catcher.php:
<?php
//if something was posted
if(!empty($_POST)){
//start an output var
$output = array();
//do any processing here.
$output['message'] = "Success!";
//send the output back to the client
echo json_encode($output);
}
It is better to use 2 files, one for the user to load that initiates the ajax call and one page to handle the ajax call. Sending an array works the same, just replace getting the textbox value with sending an array.
Instead of declaring variable toSearchArray as array. consider it an javascript object.
var toSearchArray = {}.
This is what happens when you open your page (index.php)
A GET request is issued to index.php and the content is returned. There are no values in the $_POST array so your print_r() line does nothing.
Javascript is executed that sends a POST request to index.php via AJAX. Note that this is an entirely new request, separate to the original GET. The $_POST array will be populated on this request however the response is discarded.
Hopefully this will illustrate what you can do.
ajax.php
<?php
header("content-type: application/json");
exit(json_encode($_POST));
index.php
<script>
const toSearchArray = ['some', 'array', 'with', 'values'];
$.post('ajax.php', {
variable: toSearchArray
}).done(data => {
console.log(data) // here you will see the result of the ajax.php script
})
</script>
Well I don't think thats the right way to do it when it comes to arrays, see you need to use JSON encode in javascript then JSON decode in php
Refer to this question Pass Javascript Array -> PHP
I have two separate pages, one page is where it uploads the file and the other page displays the information.
In the imageupload.php page, I have this session below:
$_SESSION['fileImage']['name'] = $_FILES['fileImage']['name'];
I also have a javascript function which calls back to the javascript functiom:
<script language="javascript" type="text/javascript">window.top.stopImageUpload();</script>
Now on a seperate page (QandATable.php), I have a javascript function, but my question is how can I call the $_SESSION code above in the javascript function so I can append it to $('.list')?
Below is javascript function:
function stopImageUpload(success){
var result = '';
if (success == 1){
result = '<span class="msg">The file was uploaded successfully!</span><br/><br/>';
$('.listImage').append('<br/>');
}
else {
result = '<span class="emsg">There was an error during file upload!</span><br/><br/>';
}
return true;
}
You cant, because $_SESSION is a server side variable but you can access it by.
For the entire session variable
<script type="text/javascript" >
var session = <?php echo json_encode($_SESSION); ?>;
</script>
For a particular variable in session.
<script type="text/javascript" >
var session_var = <?php echo json_encode($_SESSION['VAR_NAME']); ?>;
</script>
Now you have js variable called session with that information. However it is not advisable in most situation to output all that info to public pages.
Session variables are stored on the server. JavaScript is executed on the cliend side, so it knows nothing about the server side. It know only as much as you pass to it.
To pass a variable to javascript, use an ajax request, or simply output the values:
<script>
var sesionValue = <?=json_encode($_SESSION['value']);?>;
</script>
You should look into using JQuery, as it makes these AJAX-like tasks much easier.
See my function I wrote just today to do something similar to what you're asking.
This takes some PHP output (returned in the success part of the call to ajax(). The format it takes is in JSON, which is compatible by both PHP and JavaScript (JSON: JavaScript Object Notation).
function viewClientDetails(id) {
var clientParams;
clientParams.clientID = id;
$.ajax({
url: BASE_URL + '/clients/get-client-details.php',
type: 'POST',
data: clientParams,
dataType: 'JSON',
success: function(myClient) {
var name = myClient.name;
$('td#name').html(name);
},
error: function(e) {
console.log(e.responseText);
}
})
}
In my PHP file (called /clients/get-client-details.php) I have something like this:
<?php
...
$myClient = array('name' => 'Mr Foobar');
print json_encode($myClient);
?>
This simply writes my PHP object to JSON format.
In the JS code above, the code inserts a part of the JSON data into an HTML table-data element whose CSS selector ID is #name, with the line: $('td#name').html(name);
Apologies if this confuses you more, I thought I'd show an example of what you can try some time..
This may help you a bit along the way...keep trying things, you'll get there :)
You can't. $_SESSION is a PHP variable, and that code runs server-side.
You'll need to store the value as a Javascript variable in the output from your PHP file, then access that variable in your Javascript.