As the title describes it, I cannot get the value from my JQuery variable into a PHP one.

My JQuery code is like this:

$(document).ready(function() {
  var mbscr = 0;

  function checkSize() {
    if ($("#orientation").css("width") == "200px") {
      var mbscr = 1
    } else { 
      var mbscr = 2 
    }

    $.ajax({
      type:"POST",
      url: './a/cmn.arr.php',
      data: { mbscr : mbscr },
      cache: false,
      success: function(data) {
        console.log(data);
      }
    });
    return false;
  };

  checkSize(mbscr);

  $(window).resize(checkSize);
});

The PHP one is:

if(isset($_POST['mbscr']) && !empty($_POST['mbscr'])) {
    $_get_mbscr = $_POST['mbscr'];
}

var_dump($_get_mbscr);

If I use alert() instead of console.log(), the JQuery parts does its job, it alerts me what it should. My problem is I always get a null value for var_dump(), even when I do var_dump($_POST['mbscr']).

Any help will be appreciated, thank you.