HELP - added ro cart event - shopidy v 1.0 theme

I have gone through all documentation and conversations and help in community here > and still cannot get Added to Cart working
I had it working in this theme several theme versions agon - however client remvoved those theme copies

Using Turbo Florence theme 
It uses a class for add to cart > add_to_cart.action_button
Viewed product is working correctly - and I have been adding added to card snippet scrript under the Viewed product script
Is this incorrect placement?
I did try in theme.liquid without success
Previously when was working - it was added to product theme.liquid under viewed product snippet
At that time only had access to  ID for add to cart button > and I added and ID to add to cart button code in the theme to get working

>

script text="text/javascript">

var _learnq = _learnq || [];

document.getElementById("AddToCart").addEventListener('click',function (){

  _learnq.push(['track', 'Added to Cart', item]);

});

</script>

 Current code snippet I have tried  in current theme >

<script type="text/javascript">

var _learnq = _learnq || [];

  var classname = document.getElementsByClassName(“add_to_cart.action_button”);

var addToCart = function() {

_learnq.push(['track', 'Added to Cart', item]);

}; for (var i = 0; i < classname.length; i++) {

classname[i].addEventListener('click', addToCart, false);

}

</script>