<script type="text/javascript" charset="utf-8">
  $(document).on('ready pjax:scriptcomplete',function(){
 
    // Identify this question
    var thisQuestion = $('#question{QID}');
 
    // AJAX call to the PHP file
    $.get('https://pathTo/returnIP.php', function(data) {
 
      // Create an array of the IP address character sets
      var ipArray = data.split('.');
 
      // Load the text element with the first character set in the array
      $('input:text', thisQuestion).val(ipArray[0]);
    });
    });
</script>

<?php
 
  $ip = $_SERVER['REMOTE_ADDR']?:($_SERVER['HTTP_X_FORWARDED_FOR']?:$_SERVER['HTTP_CLIENT_IP']);
 
  echo $ip;
 
 
?>