I need to access a JavaScript variable with PHP. Here's a stripped-down version of the code I'm currently trying, which isn't working:
<script type="text/javascript" charset="utf-8">
var test = "tester";
</script>
<?php
echo $_GET['test'];
?>
I'm a completely new to both JavaScript and PHP, so I would really appreciate any advice.
UPDATE: OK, I guess I simplified that too much. What I'm trying to do is create a form that will update a Twitter status when submitted. I've got the form working OK, but I want to also add geolocation data. Since I'm using Javascript (specifically, the Google Geolocation API) to get the location, how do I access that information with PHP when I'm submitting the form?
This question is related to
php
javascript
variables
_GET accesses query string variables, test is not a querystring variable (PHP does not process the JS in any way). You need to rethink. You could make a php variable $test, and do something like:
<?php
$test = "tester";
?>
<script type="text/javascript" charset="utf-8">
var test = "<?php echo $test?>";
</script>
<?php
echo $test;
?>
Of course, I don't know why you want this, so I'm not sure the best solution.
EDIT: As others have noted, if the JavaScript variable is really generated on the client, you will need AJAX or a form to send it to the server.
try adding this to your js function:
var outputvar = document.getElementById("your_div_id_inside_html_form");
outputvar.innerHTML='<input id=id_to_send_to_php value='+your_js_var+'>';
Later in html:
<div id="id_you_choosed_for_outputvar"></div>
this div will contain the js var to be passed through a form to another js function or to php, remember to place it inside your html form!. This solution is working fine for me.
In your specific geolocation case you can try adding the following to function showPosition(position):
var outputlon = document.getElementById("lon1");
outputlon.innerHTML = '<input id=lon value='+lon+'>';
var outputlat = document.getElementById("lat1");
outputlat.innerHTML = '<input id=lat value='+lat+'>';
later add these div to your html form:
<div id=lat1></div>
<div id=lon1></div>
In these div you'll get latitude and longitude as input values for your php form, you would better hide them using css (show only the marker on a map if used) in order to avoid users to change them before to submit, and set your database to accept float values with lenght 10,7.
Hope this will help.
If showing data to the user, do a redirect:
<script language="JavaScript">
var tester = "foobar";
document.location="http://www.host.org/myphp.php?test=" + tester;
</script>
or an iframe:
<script language="JavaScript">
var tester = "foobar";
document.write("<iframe src=\"http://www.host.org/myphp.php?test=" + tester + "\"></iframe>");
</script>
If you don't need user output, create an iframe with width=0 and height=0.
Well the problem with the GET is that the user is able to change the value by himself if he has some knowledges. I wrote this so that PHP is able to retrive the timezone from Javascript:
// -- index.php
<?php
if (!isset($_COOKIE['timezone'])) {
?>
<html>
<script language="javascript">
var d = new Date();
var timezoneOffset = d.getTimezoneOffset() / 60;
// the cookie expired in 3 hours
d.setTime(d.getTime()+(3*60*60*1000));
var expires = "; expires="+d.toGMTString();
document.cookie = "timezone=" + timezoneOffset + expires + "; path=/";
document.location.href="index.php"
</script>
</html>
<?php
} else {
?>
<html>
<head>
<body>
<?php
if(isset($_COOKIE['timezone'])){
dump_var($_COOKIE['timezone']);
}
}
?>
I'm looking at this and thinking, if you can only get variables into php in a form, why not just make a form and put a hidden input in the thing so it doesn't show on screen, and then put the value from your javascript into the hidden input and POST that into the php? It would sure be a lot less hassle than some of this other stuff right?
As JavaScript is a client-side language and PHP is a server-side language you would need to physically push the variable to the PHP script, by either including the variable on the page load of the PHP script (script.php?var=test), which really has nothing to do with JavaScript, or by passing the variable to the PHP via an AJAX/AHAH call each time the variable is changed.
If you did want to go down the second path, you'd be looking at XMLHttpRequest, or my preference, jQuerys Ajax calls: http://docs.jquery.com/Ajax
JS ist browser-based, PHP is server-based. You have to generate some browser-based request/signal to get the data from the JS into the PHP. Take a look into Ajax.
Source: Stackoverflow.com