<script>

var stockCounter = document.querySelector('.form-group:has(.stockAvail)');


var desAttrSelector = document.querySelectorAll('#price');


for (let i = 0; i < desAttrSelector.length; i++) {

    desAttrSelector[i].addEventListener('click', checkStockValue);

}


function checkStockValue() {

    if (stockCounter.children[0].children[0].innerHTML == ': 0 available') {

        stockCounter.classList.add('soldOut');

    } else {

        stockCounter.classList.remove('soldOut');

    }

}

</script>


<style>

.soldOut {

    visibility: hidden;

    font-size: 0;

    color: red;

}


.soldOut:after {

    content: 'SOLD OUT';

    visibility: visible;

    font-size: 2rem;

    display: block;

    font-weight: 600;

}

</style>