Add to Cart button by passing product ID in HTML / JavaScript code?

I know how to create an 'Add to Cart' button on an article by simply passing in the product ID, such as '{product 132|pricedis3|pricetax1|cart|quantityfield}'. Since I don't have an option to create a button on article, but I believe we can use custom HTML & Javascript to create a 'Add to Cart' button, would please let me know if there is solution to do that?

If there is no solution, what about via PHP coding in a custom php module? is there a way to do so? Any direction on how to do it will be appreciated.

thank you!

I don't see "HTML add to cart button", am I in a wrong version of Hikashop? I see 'Add to cat HTML link', here is what I got

<a class="hikashop_html_add_to_cart_link" href="http://127.0.0.3/index.php?option=com_hikashop&ctrl=product&task=updatecart&quantity=1&checkout=1&product_id=1">Add to cart</a>

What I want:
1. A button instead of a link.
2. the Add to cart link overwrite the existing quantity, if I have a quantity of 3 for this item, and after it's 'added' (actually it's updated to), it will become one, I would expect it becomes 4, is it possible?

thank you