Getting the screen resolution using PHP

Question

I need to find the screen resolution of a users screen who visits my website?

Answer 1

JS:

$.ajax({
    url: "ajax.php",
    type: "POST",
    data: "width=" + $("body").width(),
    success: function(msg) {

        return true;
    }
});

ajax.php

if(!empty($_POST['width']))
    $width = (int)$_POST['width'];