I have a page that has 4 checkboxes that are checked by default. If you uncheck a box, it writes a cookie so that return trips to the page will have saved preferences. The problem I'm having is that the cookies seem to be written no matter what. Going to the page for the first time should create no cookies, but unchecking a box should throw the following code. As it stands, the first time I'm going to my site, the cookies are created.
Where have I gone wrong (I wouldn't be surprised if it is in multiple places).
$('#mycheckbox').change(function() {
if (! this.checked) {
<?php setcookie('key', 'Value', time() + 4800); ?>
}
});
No, this.checked works.
The problem is that the PHP code will always be run, since it's run on the server-side and not interpreted by the browser. All PHP code is executed before the browser even gets the files.
A solution would be to put that PHP in an external file and use jQuery $.ajax to request that file, which would run the code only when desired.
You could also check out the jQuery $.cookie plugin.
As #MarkB already said you are mixing up javascript and php. In this case you should set your cookie with javascript in stead of php. See this post to find out more.
The code as you have it now will always set the cookie, as you already noticed, because the server ignores the javascript code and just runs the php code to set the cookie.
Related
I am trying to delay PHP execution until a cookie is set through JavaScript. The code is below, I trimmed the createCookie JavaScript function for simplicity (I've tested the function itself and it works).
<?php
if(!isset($_COOKIE["test"])) {
?>
<script type="text/javascript">
$(function() {
// createCookie script
createCookie("test", 1, 3600);
});
</script>
<?php
// Reload the page to ensure cookie was set
if(!isset($_COOKIE["test"])) {
header("Location: http://localhost/");
}
}
?>
At first I had no idea why this didn't work, however after using microtime() I figured out that the PHP after the <script> was executing before the jQuery ready function. I reduced my code significantly to show a simple version that is answerable, I am well aware that I am able to use setcookie() in PHP, the requirements for the cookie are client-side.
I understand mixing PHP and JavaScript is incorrect, but any help on how to make this work (is there a PHP delay? - I tried sleep(), didn't work and didn't think it would work, since the scripts would be delayed as well) would be greatly appreciated.
It is not impossible to do what you are trying to do, as other answers have stated, but it is also not trivial and seriously a bad idea for your server to wait per-request for the client to "set a cookie."
But it can be done.
PHP code would write a <script> block for setting the cookie.
PHP code would begin an idle loop, monitoring a session variable. Not a cookie. The cookies for the PHP script executing are already set and are not going to change by JavaScript.
JavaScript block written in #1 would also need to make an AJAX call to the server. The PHP script it calls should set the cookie you care about, but also set the session variable #2 cares about.
The original script, monitoring the session, should wake up and continue as you planned.
While PHP does execute before JavaScript, all browsers incrementally load the HTML/CSS/JavaScript content generated by PHP (or any server-side language). Because of the incremental loading, it is possible for your PHP script to delay for JavaScript to do something (as outlined above) before continuing. But your server is going to have a lot of headache to deal with, such as how long to wait for JavaScript to break the idle loop in #2 if the JavaScript request never comes through, etc.
This is not a normal execution flow for a standard webpage. Unless you really need this, perhaps consider this a proof-of-concept answer.
PHP executes first in its entirety on the server. It then sends the final HTML/Javascript/CSS output to the browser. The browser receives this and executes any Javascript.
It is fundamentally impossible to do what you're trying to do with that code. PHP and Javascript run at completely different times in completely different environments. You need to start another request to the server once Javascript set the cookie to start another PHP script. Redirect using Javascript or look into AJAX.
If you want to execute JavaScript before PHP, you'll have to divide it into two requests. You can load your JavaScript in one request, and execute an Ajax request after your cookie is set. Keep in mind that all server-side code is processed before the client-side code will be executed.
I have to ask though.. why do you want to do it this way? What are you trying to accomplish?
Cookies can be set in PHP with setcookie
setcookie("test",1,time()+3600);
This can't be done within a single request. PHP runs first, then JavaScript. Even incremental loading won't help, because cookies are sent via headers and those have already been sent by the time PHP runs.
However, you can let the JavaScript set the cookie and then reload the page once it's done by using location.reload(). PHP would then only need to print the JavaScript, like so:
<?php
if(!isset($_COOKIE["test"])) {
?>
<script type="text/javascript">
$(function() {
// createCookie script
createCookie("test", 1, 3600);
// reload the page, which would send the cookie at the next request
location.reload();
});
</script>
<?php
// stop execution and wait for JavaScript to call you again.
exit;
}
?>
The PHP executes on the server-side, the JS on the client-side. In a single GET request from the browser, the PHP will always execute before the JS.
i've got a slight problem with JS enabled detection.
not too big, because i know i'm on the right track.
but here's my deal:
when i try to set a cookie in JS (jQuery) using this code
$(window).load(function(){
$.cookies.set('c_jsEnabled', 'true');
});
or just in plain JS using this code
function setCookie()
{
document.cookie='c_jsEnabled=true';
}
<body onload="setCookie();">
and then try to detect it in PHP using this code
if($_COOKIE['c_jsEnabled'] == 'true')
{
if(file_exists('./main.php'))
{
require_once ('./main.php');
}
echo getIndex();
}
else
{
if(file_exists('./noJS.php'))
{
require_once ('./noJS.php');
}
echo getIndex();
}
setcookie('c_jsEnabled', '');
it takes 2 page refreshes to actually get the right value into PHP.
my guess is that this bascially means that the PHP script is executed before the JS function is fired.
could this be because all codes shown above are in the same script (index.php)?
This is kind of a problem for me, because i want to prevent people from using my website when they have JS disabled.
is there a way to set the cookie before php tries to get the cookie variable?
PHP is always "fired" before JavaScript because PHP is processed on the server and then sends out the HTML and JavaScript for the browser to process and render. You can never expect JavaScript to execute before PHP for this reason.
In your case, use JavaScript to set the cookie and then do a redirect to refresh the page so PHP can get the cookie value and act accordingly.
You should be setting the cookie directly from the PHP file. That way, you know that it exists, and more importantly, you have control of the cookie. You can set it from the client, but that will always execute after the HTML has been sent to the browser, so the PHP file won't get it until the next request.
PHP only sends the cookie header when content is sent to the browser. Javascript then executes after that, so you would need a second load of the page to detect the cookie.
This can trigger infinite redirection loops (especially if the user has cookies disabled), so be careful.
To disable the site to users without Javascript, consider the following.
<div id="noscript" style="width:100%; height:100%; z-index:999; position:absoloute; top:0px; left:0px; background-color:#CC9900; display:block">
Please Enable Javascript!</div>
<script type="text/javascript">
document.getElementById('noscript').style.display = 'none';
</script>
I find the <noscript> tag is unreliable (there was a bug in iOS causing it to only show when there was Javascript, if I remember correctly).
A second option:
You can have the PHP check for a cookie. If it isn't set, have it redirect (header("Location: aaa.html");) to a page with the Javascript to set the cookie and redirect back. (Alternatively, have the PHP output Javascript to set the cookie reload the page.) You then only have to worry about users who "spoof" the cookie, although you will also lock out users who have cookies disabled.
Nope - PHP will always be called before client-side JavaScript, so with this method you'll always have to refresh the page at least once. You're better to develop your site so that non-JS users have a worse-but-still-acceptable experience, or at worst use the <noscript> HTML tag to serve alternative content to those users.
You can't get a cookie in PHP that's being set by JavaScript before the page renders/executes.
You could set the cookie using PHP, however. That will ensure it's set and available regardless of JavaScript or multiple page refreshes.
I am developing w php web site. Here I have set a php cookie
setcookie('hotelId',$resHotel);
I want to check whether it’s set or not using jquery or javascript. I have used the following code
if($.cookie('hotelId')) {
alert("yes");
};
But it's not working
Is there is any way to find PHP cookie is exist or not in jquery
Thanks
That should work if these two conditions are met:
you have installed the extra library that you need to use $.cookie()
you have called setcookie() before outputting any part of your html
Are you sure that you have the right libraries loaded into the page? I don't think cookie behavior is included with jQuery by default.
You can view cookies manually easily. The method varies a little from browser to browser, but (in Firefox, for example) if you go to Preferences > Privacy > remove individual cookies, you can browse through them and see their contents. This can help you debug whether your php code is setting the cookie as desired.
First get the specified cookie as follows
var cookie=$.cookie("set");
if(!cookie)
{
$.cookie("set","foo"); //if there is no cookie set it
}
I have a situation like this.
<php>
<redirect the page >
<exit>
<javascript>
<redirect the page again>
I want to have javascript that basicall disables the PHP redirect. So if Javascript is enabled on the browser, the javascript redirect will work, if it disable, the PHP redirect will work. Should I just enclose the PHP code in span and make it invisible? Any ideas?
Addition ok this is not a simple redirect. the form authentication is rather odd. Register.php -> register_submit.php -> Was there an error -> yes go back to register.php (everything is javascript at this point). What I have added is PHP authentication as well so if I see javascript is not enabled, I take the user to register.php *after it does the regular checking of fields *.
PHP is a server-side technology. By the time Javascript even sees what's happened, it's too late.
Short answer, JS can't intercept/block PHP (as long as PHP is being called first).
Order of events:
Client requests page
PHP executes and generates output of page
Browser receives output
Browser begins parsing what was sent by what PHP already spit out.
Remove your PHP redirection and add this in your <head>:
<noscript>
<meta http-equiv="refresh" content="0; http://www.example.com/1" />
</noscript>
<script>
window.location = 'http://www.example.com/2';
</script>
This will redirect to http://www.example.com/1 when javascript is disabled, and to http://www.example.com/2 when it's enabled.
PHP code is executed on the server-side, while JS is client-side. So with that structure the PHP will kick in before the JS is executed. If you want JS to control PHP you need to make use of AJAX to control it.
Also enclosing PHP code in a "span" won't have any effect.
Javascript and PHP do not directly interact (exceptions apply, don't worry about them now :D). The best way to implement this type of interaction between these two disparate languages is to use the query string or cookies.
I think there may be some confusion here about when and how PHP is executed as opposed to when and how javascript is executed. Think of PHP as the factory - the goods are physically produced there. Think of your server as the loading dock, the internet as the shipping company. Your browser is the store, HTML is the shelves; Javascript is the window decorations on the store that sells the merchandise. The window decorations have no affect on the production, the factory can make some window decorations, but it doesn't use them, it just ships them right along with the merchandise for the store to use. PHP is the factory, javascript is the decoration. There are some problems with taking this analogy too literally, but there it is in a nutshell.
You can make the PHP redirect conditional on the presence or absence of a specific query string variable:
<?php
// redirect if $_GET['no_redirect'] is NOT set. Reverse the true/false to invert this rule
$do_redirect = (isset($_GET['no_redirect']) === false ? true : false);
// perform the redirect, if required
if ($do_redirect === false)
header('Location:http://mydomain.com');
?>
Javascript:
window.location = 'http://mydomain.com/?no_redirect=1';
EDIT If you're trying to detect if javascript is enabled, then the best way is for javascript to set a cookie if it is enabled. PHP can then check for this cookie, and if it isn't found then you'll know that javascript didn't get a chance to set it, so it must be disabled (or the user edited their cookies).
Take a look at some code snippets for dealing with cookies in javascript, and check out the documentation for dealing with cookies in PHP.
I set the cookies regularly in a callback page in my Twitter application. Everything works fine.
Now, using jQuery, I submit a form, and the callback function activates a PHP script. That script only needs to set one cookie to the serialized values of $_POST; and the values run fine (both serialized and normal, I echoed them out to debug). The expiration time is set to 1 year ahead. But for some reason, the cookie just won't appear anywhere. Here's the code:
// js/main.js
$('#settings-form').live('submit', function() {
$.post('controllers/settings.php', $(this).serialize(), function(data) { // Everything here works.
if (data == 'OK') // no errors spits out "OK". this works
changeView({'msg': 'Your settings were saved successfully.'}); // This just resets the view and adds a message div at the top. This works
else
changeView({'msg': data}); // This echoes the error if any exists. Doesn't happen, no errors arise
});
return false; // Cancels redirecting after submitting form
});
// controllers/settings.php
setcookie('user_settings', serialize($_POST), strtotime('+1 year'));
I checked all the variables and I even tried setting dummy ones for test (like "boo" instead of serialize($_POST). for some reason that doesn't work.
Any ideas why this is happening? I tried doing a chdir('..'); to make the cookie dir go to the right place, but that doesn't seem to be the problem, checking the cookies inside my browser doesn't seem to work at all, for any path. It just doesn't work at all. I also just tried manually changing the domain and path, but those don't work either.
Firstly, the chdir() thing is a red-herring -- Cookies are domain-specific; the directory path doesn't have any bearing on them.
Cookies can work a bit strangely when you're making ajax type calls, and I think this is what you're seeing -- The server is probably setting the cookie, but the browser may not be setting it in the cookies data it as it's not a page load.
I would suggest you'd be better off using PHP's session handling rather than cookies; it's better for security, less bandwidth (because the whole of the cookie data is transmitted in both directions with every http single request), and more likely to work.
If you really want to use cookies, it may work better if you use Javascript to do it. You can set cookies in your javascript code by accessing document.cookie. (you need to get the syntax right for the cookie string, but JQuery probably has its own functions that makes them easier to work with)