Thanks for your reply.
I've implemented your javascript code on my Cart button in product-list.tpl. But its not working. I think ajax call on cart button has been blocked this code.
<script type="text/javascript">
function changeBG() {
document.getElementById("cartbutton").style.backgroundColor = "#83E02F";
}
</script>
<a id="cartbutton" class="button ajax_add_to_cart_button cart_button" href="{$link->getPageLink('cart',false, NULL, "add=1&id_product={$product.id_product|intval}&token={$static_token}", false)|escape:'html':'UTF-8'}" rel="nofollow" title="{l s='Add to cart'}" data-id-product="{$product.id_product|intval}" onclick="changeBG()">
You can use page source to see my script in this page http://www.drucken24.at/465-intec
Please help.