[code]<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script>
<script>
$(window).ready(function() {
    var wi = $(window).width();
    $("p.testp").text('Initial screen width is currently: ' + wi + 'px.');

    $(window).resize(function() {
        var wi = $(window).width();
		var jsp = 0;


        if (wi <= 1024){
			jsp = 3;
		}else{ jsp = 2;}

    });
});
</script>

<?php

(...)

$jsp = 3;

$jsp = $params->get('jsp',0);
switch($jsp){
  case 2:
    $slide_size = $width;
    $count = 1;
    break;
  case 1:
    $slide_size = $height + $spacing;
    break;
  case 0:
  default:
    $slide_size = $width + $spacing;
	break;
}[/code]