CS-CART 2.1.4 - Place Order Checkout Button - Change to Click Once

Hi, Looking for a small change to our CS-CART system, The checkout system currently allows the place order button to be clicked multiple times if server response is slow, We want the smarty code in [login to view URL] to be modified to grey out when the button is submitted. The template system uses smarty system, code below {include file="buttons/[login to view URL]" but_text=$lang.place_order but_name=$but_name but_href=$but_href but_target=$but_target but_role="big"} Stephen