Capture session_id into cookie

capture pixel.php

<?php

$offerId = intval($_GET['offer_id']);
$orderId = $_GET['adv_sub'];
$amount = floatval($_GET['amount']);
$transactionId = $_GET['transaction_id'];


//do whatever you want to do with the variables
//ie cross check database for clicks and save into database
//printf("Offer ID %d<br>",$offerId);
//printf("Order ID %s<br>",$orderId);
//printf("Amount %.2f<br>",$amount);
//printf("Transaction ID %.2f<br>",$transactionId);

//show 1x1 pixel gif image
header('Content-type: image/gif');
$content = base64_decode('R0lGODlhAQABAJAAAP8AAAAAACH5BAUQAAAALAAAAAABAAEAAAICBAEAOw==');
echo $content;

capture.js

<script>
  var ssSessionId = ssGetURLParameter('session_id');
  var ssDocName = 'SSSID';
  var ssDataExpired = ssCalculateExpireDate(30);
  
  if (ssSessionId !== null) {
    ssSetCookie(ssDocName, ssXSessionId, ssDataExpired);
  }

  function ssGetURLParameter(name) {
    return decodeURIComponent((new RegExp('[?|&]' + name + '=' + '([^&;]+?)(&|#|;|$)').exec(location.search)||[,""])[1].replace(/\+/g, '%20'))||null
  }

  function ssSetCookie(cName, cValue, exDate) {
    var expires = "expires="+exDate;
    document.cookie = cName + "=" + cValue + "; " + expires + "; path=/";
  }

  function ssCalculateExpireDate (days) {
    var d = new Date();
    d.setTime(d.getTime() + (days*24*60*60*1000))
    d.toUTCString()
    return d;
  }
</script>

fire_pixel.js

<script language="javascript" type="text/javascript">
<!-- Start of ShopStylers GTM Tag -->
<!-- Please do not modify -->
  
var ssOrderID = document.getElementById("SX-GTM-orderid").innerHTML;
var ssAmount = document.getElementById("SX-GTM-total-amount").innerHTML;

function getCookie(cname) {
    var name = cname + "=";
    var ca = document.cookie.split(';');
    for(var i=0; i<ca.length; i++) {
        var c = ca[i];
        while (c.charAt(0)==' ') c = c.substring(1);
        if (c.indexOf(name) == 0) return c.substring(name.length, c.length);
    }
    return "";
}
var ssSessionID = getCookie('SSSID');

if(ssSessionID !== "") {
  var ssUrl = "https://xxx.xxx.com/aff_l?offer_id=xxx" +"&adv_sub=" + ssOrderID + "&amount=" + ssAmount +"&transaction_id=" + ssSessionID;

var iframe;
iframe = document.createElement('iframe');
iframe.src = ssUrl;
iframe.width='1px';
iframe.height='1px';
iframe.scrolling='no';
iframe.style.display = 'none';
document.body.appendChild(iframe);
}
<!-- End of ShopStylers GTM Tag -->
</script>