need a javascript fix for form button and lightbox

I have a product page on an e-commerce site and the "add to cart" button code looks like this: <form method="post" action="[login to view URL]" id="form1" name="form1"> ... <div id="cart"><button class="button" name="Add_to_cart" value="1"><i class="fa fa-shopping-cart"></i> Add to Cart</button> </div> ..... </form> I want to implement this lightbox [login to view URL] on the "add to cart" button above so the lightbox pops up when the button is clicked HOWEVER the button should still function to actually ADD THE ITEMS TO THE CART. I have this lightbox working on another part of this web page, but that is just on a simple link. GOAL: When clicked, the add to cart button needs add the items to the cart PLUS open a lightbox (I will already add my own content to the lightbox). The site is coded with asp.net and I think this can be fixed with javascript, but whatever solution works is fine.