document.getElementById('prod_addcart21').addEventListener('click', function () {
        if ($('select[name="variation[1]"]').val() == '') {
                alert('Please, choose an option 1');
            return false;
        } else if ($('select[name="variation[2]"]').val() == '') {
    
            alert('Please, choose an option 2');



        } else if ($('select[name="variation[3]"]').val() == '') {

            alert('Please, choose an option 3');


        } else {
            alert("product added to cart")
        }
    

    });