Thanks again Jason,
Would that code also block the Clear Cart & Update buttons? They don't seem to be functioning.
I may have things screwed up in the browser, I had > 10 items in the cart, then I modified the code per your suggestions, witout first clearing the cart.
I've fiddled around so much that it may be best to recreate the page, now that I have a plan in place.
Update, I tried it from another computer, and at qty > 10 ALL buttons seem disabled.
Here is the link, if it should be useful. TshirtOrderForm.php