Why won't this var change value?

Why won't this var change value?

So I have this jquery code and it works except for one specific part. I am doing a quantity check for a shopping cart system and I need to prevent the default form submission of the submit button and check all the quantities with a $.post() and checking the database. I have confirmed that all aspects work for the checking and outputting to the screen when and where they need to. If I alert(bad) inside the else{} it shows me the value I expect but it does not seem to hold that value or something after the .each() runs which is where I check it's value and submit the form if it's still false in value. Any insight would be great. 
  1.     
      
     
    1. $('#paypal-submit-button').click(function(e){
      2. 
     
    2.         var bad = false;
      3. 
     
    3.         e.preventDefault();
      4. 
     
    4.         $('.qty-input').each(function(){
      5. 
     
    5.             var qty = parseInt($(this).val());
      6. 
     
    6.             var id = parseInt($(this).attr('prod_id'));
      7. 
     
    7.             var qty_id = String($(this).attr('qty-input-num'));
      8. 
     
    8.             
      9. 
     
    9.             $.post('check_avail_qty.php', {pid:id, quantity:qty}, function(data){
      10. 
     
    10.                 if(data == "good")
      11. 
     
    11.                 { }
      12. 
     
    12.                 else
      13. 
     
    13.                 {
      14. 
     
    14.                     $('#prod-qty-check'+qty_id).html('Oh No! It seems we have run out of this item. Please remove it from your cart to continue.'); 
      15. 
     
    15.                     var bad = true;
      16. 
     
    16.                     alert(bad);
      17. 
     
    17.                 }
      18. 
     
    18.             });
      19. 
     
    19.         })
      20. 
     
    20.         if(bad === false){ $('#cart-submit-form').submit(); }
      21. 
     
    21.     });
      22.