al().replace(/[^\d.-]/g, '')
          if ($('#thickness-toggle').is(':checked') && thickness == '') {
            $('#thickness').addClass('ui-state-error');
            $('#thickness').siblings('.error-msg').append('<div>If plate thickness is turned on you need to specify a value.  If you turn it off, it will default to 1.5 (mm).</div>');
            error_els.push('#thickness');
            has_error = true;
          } else {
            if ($('#thickness-toggle').is(':checked') && thickness != '') {
  