php/js results differ on mobile device

[cloudll]

Hey guys,

 

I am using this code to use javascript to send the browser window width to a php session variable.

session_start();

$parentDir = basename(dirname($_SERVER['PHP_SELF']));;

if (!isset($_SESSION['screenWidth'])) {
    echo '<script>window.location = "' . "/" . $parentDir . "/" . '?width="+window.innerWidth</script>';
    if (isset($_REQUEST['width'])) {
        $_SESSION['screenWidth'] = $_REQUEST['width'];
        header("Location: " . "http://" . $_SERVER['HTTP_HOST'] . "/" . $parentDir);
    }
}

it works fine on my pc, however, when I try it on my phone it returns a width value of 900, which is wrong.

 

If i add the javascript directly it returns a true value of 350.

<button onclick="myFunction()">Get Width</button>
<script>
function myFunction() {
    alert(window.innerWidth);
}
</script>

I know this isn't just php but I was hoping someone would have any idea as to whats going on? Thanks for any help

 

EDIT: I uploaded a demo: http://www.myprimaryweb.co.uk/checkWidth/

Edited February 11, 2016 by cloudll

[QuickOldCar]

Not all devices and browsers work the same.

 

If can do what you need using css and media queries will be better off.

 

Here's something I did a few years back for a client for saving some sizes dealing with video content areas.

<?php
if(isset($_COOKIE["screen_width"]) && trim($_COOKIE["screen_width"]) !=''){
$screen_width = trim($_COOKIE["screen_width"]);
$screen_width = calc_res($screen_width, 66, 2);
$screen_height = round($screen_width / 1.78);
}else{
?>
<script type="text/javascript">
var winW = '';
if (document.body && document.body.offsetWidth) {
 winW = document.body.offsetWidth;
}
if (document.compatMode=='CSS1Compat' &&
    document.documentElement &&
    document.documentElement.offsetWidth ) {
 winW = document.documentElement.offsetWidth;
 }
if (window.innerWidth) {
 winW = window.innerWidth;
 }
 
var winH = '';
if (document.body && document.body.offsetHeight) {
 winH = document.body.offsetHeight;
}
if (document.compatMode=='CSS1Compat' &&
    document.documentElement &&
    document.documentElement.offsetHeight ) {
 winH = document.documentElement.offsetHeight;
 }
if (window.innerHeight) {
 winH = window.innerHeight;
 }
 if(window.innerWidth <= 800 && window.innerHeight <= 600) {
     winW="640";
     winH="480";
   }
function setCookie(c_name,value,exdays,domain,path){
      var exdate=new Date();
      exdate.setDate(exdate.getDate() + exdays);
      var c_value=escape(value) +
        ((exdays==null) ? "" : ("; expires="+exdate.toUTCString()));
        cookie=c_name + "=" + c_value;
 
  if (domain){
    cookie += "domain=" + domain + ";";
    }
    if (path){
    cookie += "path=" + path + ";";
    }
      document.cookie=cookie;
    }
    
    setCookie("screen_width",winW,60,"/",".site.com");
    setCookie("screen_height",winH,60,"/",".site.com");
</script>
<?php
$screen_width = "100%";
$screen_height = "600";
}//end set screen size cookie
?>