var filter_caterer = $('#filter_caterer').val();

            if (filter_caterer !== '') {

                url += '&filter_caterer=' + encodeURIComponent(filter_caterer);

            }

var mySelect = $('select[name=' + name + ']')

    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")

        }

​

    });