如何存储在php变量中的函数中找到的javascript变量值

Question

I'm trying to store the user's current latitude and longitude info as a PHP variable $lat . Since it's in a function userLocated the value is not obtained. Here's the code:

<script type="text/javascript">

        navigator.geolocation.getCurrentPosition(userLocated);

        function userLocated(position){
        var latitude = position.coords.latitude;
        var longitude = position.coords.longitude;
        // document.write("latitude: " + latitude +" longitude " + longitude);

    }

</script>

<?php 

$lat ="<script> 
document.writeln(latitude); 
</script>"; 
echo "$lat";
?>

Answer 1

That is not how JavaScript and PHP interact with each other.

PHP runs on the server and does it's job long before the user actually sees the website.

JavaScript runs on the browser (in this case anyway) and does it's job long after PHP has done it's.

What you are trying to do, the way you are trying to do, simply doesn't work. You will need to obtain the info with JS and then post it (either via a XHR request or with a form) to the server where PHP can do with it whatever it wants. But you need to understand that that will be two entirely separated processes.