Develop Reference

Check if the value of the local storage is equal or not to that of a Php variable

hello I have this php file with the name ** request.php ** that has this Code:
<?php
$Password_user = 'AIzaSyA';
?>
and I have a Index.html file, and I also have a Local Storage with that name user_pass so I created a variable with the name get_spass that looks like this:
var get_spass= localStorage.getItem('user_pass');
so how can i create a request in Ajax that is able to check if the value of the Storage location is equal or not gives it Variable ** Password_user of request.php?

You have to change your php file to:
<?php
$Password_user = 'AIzaSyA';
echo $Password_user;
?>
In your html file you can fetch the file and check the password value with this code:
var get_spass= localStorage.getItem('user_pass');
var passIsCorrect = checkPassword(get_spass);
if (passIsCorrect) {
//do stuff...
}
async function checkPassword(get_spass) {
const passwordPhp = await fetch("request.php");
if (get_spass === passwordPhp) {
return true;
}
return false;
}
Note that everyone can get the request.php content. If the password need to be secret you have to implement some sort of authentication to assure the request.php file can be read only by authorized users or person.

PHP not accessing Javascript cookie

I am creating a small CRUD web app where I need the user to enter their password when they wish to delete an item from the database, I have an onClick() on the delete button on the HTML table which passes the ID of the product to be deleted to the js function.
When the function runs I wish to confirm that they really want to delete the product and then ask for their password and store it in a cookie. BUT IT DOES NOT SEEM TO WORK :(
I am setting a cookie using javascript like
document.cookie = 'password=${userPassword},expires=${now.toGMTString()},path=/../includes/delete-product.inc.php;
With this line of code, when I console.log(document.cookie), it shows me the cookie in the console like
password=admin,expires=Sat, 12 Dec 2020 08:40:38 GMT,path=/../includes/delete-product.inc.php; PHPSESSID=3n1l3q6ksqitdpc76hjrero9ja
when I redirect to another PHP page using window.open() I can not access this cookie.
print_r($_COOKIE); <- only shows me the PHPSESSID only.
When I explicitly try to access the cookie using the following line
$userPassword = $_COOKIE[password]; it gives me undefined index 'password'
This is my code.
myproject/admin/view-products.php (This is the page where I try to set the cookie using javascript)
function deletePrompt(id) {
const now = new Date();
const time = now.getTime();
const expiresIn = time + (50 * 1000);
now.setTime(expiresIn);
const path = `../includes/delete-product.inc.php`;
const intent = confirm("Are you sure you want to delete this products");
if (intent === true) {
const userPassword = prompt("Enter password");
document.cookie = `password=${userPassword},expires=${now.toGMTString()},path=/../includes/delete-product.inc.php`;
console.log(document.cookie);
return;
window.open(`../includes/delete-product.inc.php?id=${id}`, "_self");
}
}
myproject/includes/delete-product.inc.php (This is the PHP page where I need to access the cookie)
<?php
require_once "./database-connection.inc.php";
require_once "./functions.inc.php";
if (isset($_SESSION["adminId"])) {
$productId = $_GET["id"];
$userPassword = $_COOKIE["password"]; //<- This throws undefined index error
if (deleteProduct($connection, $productId, $userPassword)) {
header("location: ../admin/view-products.php?msg=deleted");
exit();
}
else {
header("location: ../admin/view-products.php?msg=incorrectPass");
exit();
}
}
else {
header("location: ../admin/login.php");
exit();
}

To anyone else facing this the problem, the solution is that cookies don't get sent across directories, so you need to have the recipient file in the same domain if you wish to transfer cookies across them otherwise it won't work.
eg.
Following pattern will work
youProject/someDirectory/file1
youProject/someDirectory/file2
Following will NOT WORK
youProject/someDirectory/file1
youProject/someOtherDirectory/file2

create a session using php and ajax

I am beginner in web development so please understand me. I am trying to create a session using php file and call it in javascript using ajax request. but after I input the path of the index.html in address bar, it always shows the index. I want to know how can i possibly do this with javascript and php. restricting the all the pages of the site if there is no user active.
for example logic:
if (userhasValue == true) {
//redirect to index and can access the whole website
} else {
// redirect to login page
}
I have tried the code below but it still redirecting to index.html even if the data recieve in ajax request is empty.
<?php
include('config.php');
session_start();
$user_check = $_SESSION['login_user'];
$temparray = array();
$ses_sql = mysqli_query($db,"select user_id,username,fullname from user where username = '$user_check'");
$row = mysqli_fetch_array($ses_sql,MYSQLI_ASSOC);
if ($row > 0 ){
array_push($temparray, $row); //save your data into array
echo json_encode($temparray);
} else {
echo 'Error';
}
?>
function getUser(){
var user ='';
var fullname ='';
var id ='';
var tempArray = '';
var name = '';
$.ajax({
type:'POST',
url:'../bench/php/session.php',
data:'',
success:function(msg){
alert(JSON.stringify(msg));
let tempArray = JSON.parse(msg)
user = JSON.stringify(tempArray[0]['username']);
fullname = JSON.stringify(tempArray[0]['fullname']);
id = JSON.stringify(tempArray[0]['id']);
document.getElementById('fullname').innerHTML = fullname;
if (msg == 'Error') {
window.location.href = "../pages-login.html";
}
}, error: function(e){
console.log(e);
}, complete: function(c){
console.log(c);
}
});
}
The code above does not restrict the accessibility of the index.html and other pages if the user is not logged in.
I want to restrict the index page and other pages if the user try to redirect to index page without logging in.
Please help me. Any help will much be appreciated! Thanks in advance

Creating a Cookie to not vote again in a poll

I've created a simple [voting form] using jQuery AJAX and JSON. I want to know how to create a Cookie so that the user will not be able to vote more than once. Following is my code.
I am new to Cookies and jQuery. Please tell me how to complete my task.
JavaScript
<script>
$(document).ready(function(){
$("#poll").click(function(){
var count = '';
if (document.getElementById("vote1").checked) {
count = 0;
}
if (document.getElementById("vote2").checked) {
count = 1;
}
var jsonV= { "vote": count };
$.ajax({
type : "POST",
url : "poll_vote.php",
data : jsonV,
dataType: "json",
success : function ( responseText ){
console.log("Is working " + responseText);
$("#result").html( responseText.vote );
},
complete : function(){
$("#poll").slideUp();
},
error : function( error,responseText ){
// alert("Server not Responding. Sorry for the inconvenience caused. Please Try again Later");
console.log( error );
$("#result").html( error + responseText );
alert( count );
}
});
});
});
</script>
PHP
<?php
$vote = $_REQUEST['vote'];
$filename = "poll_result.txt";
$content = file($filename);
// $decode = json_decode($encode);
$array = explode("||", $content[0]);
$male = $array[0];
$female = $array[1];
if ($vote == '0') {
$male = $male + 1;
}
if ($vote == '1') {
$female = $female + 1;
}
$insertvote = $male."||".$female;
$fp = fopen($filename,"w");
fputs($fp,$insertvote);
fclose($fp);
$table = (
"<h2>Results:</h2>
<table>
<tr>
<td> Male :</td>
<td>
<img src='poll.gif'
width= ".(100*round($male/($female+$male),2)).
"height='20'>".
(100*round($male/($female+$male),2))." %" .
"
</td>
</tr>
<tr>
<td> Female :</td>
<td>
<img src='poll.gif'
width=". (100*round($female/($female+$male),2)) .
"
height='20'>".
(100*round($female/($female+$male),2))." %" ."
</td>
</tr>
</table>"
);
$list = array('vote' => $table);
$encode = json_encode($list);
echo $encode;
?>
HTML
<div id= "poll">
<h3> What is your Gender? </h3>
<form>
Male :
<input type ="radio" name ="vote" id="vote1" >
<br>
Female :
<input type ="radio" name ="vote" id="vote2" >
</form>
</div>

You would want to set a cookie when the user votes, and check for that cookie in PHP when a vote is submitted. If the cookie is already set, the vote should be discarded.
For example, using just PHP, it could look something like this:
if (!isset($_COOKIE['has_voted'])) {
// normal vote submission code goes here
// ...
// then we set a cookie to expire in 30 days
setcookie('has_voted', '1', mktime().time()+60*60*24*30);
} else {
// cookie already exists, user has already voted on this machine
// do not count the vote, flag an error to the user
}
It is worth noting that there are ways round this - the user could easily delete the cookie manually. In this case, you could also store the IP addresses of users who have already voted, but this can open up problems on shared machines and multiple machines behind a network.

Since it seems you're using PHP, you'll be able to implement a cookie to prevent multiple votes within your already existing script.
The syntax for setting a cookie in PHP is as follows:
setcookie("cookiename", "cookiedata", cookietime, "cookielocation");
Where "cookiename" is the name of the cookie, for example, "voted", "cookiedata" is the data stored in the cookie– "yes", for example. "cookielocation" is the location where the cookie is stored in the user's browser cache. Unless you know what you're doing, just set this to "/".
Cookietime is how long the cookie will sit in the users system until the browser automatically deletes it. Note that this doesn't prevent the user from deleting the cookie. For simplicity, I usually set the time as follows:
time()+60*60*24*days
Where days is how long the cookie will sit in the user's system (in days, of course).
To retrieve the value of a cookie so you're able to perform logic on it, try using:
if(isset($_COOKIE['cookiename'])) {
$valueOfCookie = $_COOKIE['cookiename'];
}
Make sure to use the if(isset()) to make sure the cookie has been set, before trying to retrieve the value.
Using these functions, your logic may look something like this when the user submits the form:
Check if the voting cookie is set
If it is, print an error message, else:
Continue to process the form data, and set the vote cookie
However, on a side note, if you're concerned about users potentially deleting their cookies so they can vote again, I might suggest that, rather than using cookies, you store users' IP addresses on the server-side, and deny them voting access if their IP address has already voted.

You could do this with sessionStorage, using only JS:
<script>
$(document).ready(function(){
$("#poll").click(function(){
var count = '';
if (document.getElementById("vote1").checked) {
count = 0;
}
if (document.getElementById("vote2").checked) {
count = 1;
}
var jsonV= { "vote": count };
if ( sessionStorage.getItem( 'voted' ) == 'true' ) {
alert('You have already voted!');
}else if ( sessionStorage.getItem( 'voted' ) == null ){
$.ajax({
type : "POST",
url : "poll_vote.php",
data : jsonV,
dataType: "json",
success : function ( responseText ){
console.log("It's working" + responseText);
$("#result").html( responseText.vote );
},
complete : function(){
$("#poll").slideUp();
sessionStorage.setItem('voted', 'true');
},
error : function( error,responseText ){
// alert("Server not Responding. Sorry for the inconvenience caused. Please Try again Later");
console.log( error );
$("#result").html( error + responseText );
alert( count );
}
});
}
});
});
</script>
What I have done here is added a session storage item in the
complete callback of your ajax call, so once it has completed the
item 'voted' will be set.
I have then wrapped the ajax call in an if condition which checks
the value of the storage item and if it is set then will not allow
you to vote (and instead bring up an alert)
Note that you can also you localStorage if you want the item to last longer as sessionStorage is cleared when the browser window is closed while localStorge will last until the user clears their cookies / browsing data.
And here is a little snippet you can use to clear the storage for testing purposes:
$('#clear').click(function(){
console.log(sessionStorage.getItem( 'voted' ));
sessionStorage.removeItem('voted');
console.log(sessionStorage.getItem( 'voted' ));
});
You will need the accompanying HTML with that:
<p id="clear">clear</p>

Post Javascript to PHP and then retrieve in another javascript

I m trying to post the value from my java_post.js into php_post.php and then retrieve in another javascript page, index.html. So far i can post the value into the php_post.php and retrieve back into my java_post.js as alert(data)
but i cannot retrieve from my index.html
Java_post.js
var url_link ="index.html";
//On Click Select Function
$("#table_hot").on('click', 'tbody tr',function(){
$(this).addClass('selected').siblings().removeClass('selected');
var value=$(this).find('td:first').html();
$.post('PHP_post/php_post.php',
{
postvalue:value
},
function(data){
alert(data);
}
);
});
//Window Pop Out Function
function hotspot_pop(url_link){
newwindow = window.open(url_link, '', "status=yes,
height=500; width=500; resizeable=no");
}
The value is retrieve when the client click the selected table and then post into the php_post.php. The php_post.php will filter the result and return to index.html.
$filtered_students = array_filter($ARRAY, function($row) {
$hotspot_value = $_POST['postvalue'];
if($row['name'] == $hotspot_value){
return true;
}
});
echo $filtered_students;
So now i m able to retrieve the value and post into as an alert for my java_post.js but the value is no pass into index.html and i receive the error for undefined postvalue.
<html>
<script src="js/jquery-1.11.1.min.js"></script>
<body>
<div id="result"></div>
<script>
var xmlhttp_user = new XMLHttpRequest();
var url_user = "PHP_post/php_post.php";
xmlhttp_user.onreadystatechange=function() {
if (xmlhttp_user.readyState == 4 && xmlhttp_user.status == 200) {
document.getElementById("result").innerHTML=xmlhttp_user.responseText; }
}
xmlhttp_user.open("GET", url_user, true);
xmlhttp_user.send();
</script>
</body>
</html>
So my problem is now, is there any method that allow me to show the value in index.html from php_post.php. As a reminder the alert(data) from java_post.js is just a testing purpose to show the value did post and return from php_post.php

The issue you're having is that when you pass the data into your PHP file and receive the data back in your JavaScript, the information only lasts as long as your current request.
To fix this issue, consider using PHP Session variables to store your data, so that you can retrieve it later.
Example:
// php_post.php
<?php
start_session(); // initializes session for persistent data
$filtered_students = array_filter($ARRAY, function($row) {
$hotspot_value = $_POST['postvalue'];
if($row['name'] == $hotspot_value){
return true;
}
});
$_SESSION["filtered_students"] = $filtered_students; // You can now retrieve this in
// Another PHP file
?>
Now in another file (you would switch your HTML file to get from php_get.php):
//php_get.php
<?php
start_session(); // Don't forget to start the session
echo $_SESSION['filtered_students'];
?>
More information here: http://www.w3schools.com/php/php_sessions.asp

You can set the desired value into PHP session while at php_post.php.
This way, you can retrieve the session's value on any page you desire.