Shopify Ajax Update Cart - shopify

Question

I want to be able to update my cart when I click on the increase button without having to click update button
Here is my script
<script>
let classlist = []
let val = document.querySelector('.qty-select')
let classes = document.getElementsByClassName('val')
for (var i=0; i<classes.length; i++) {
classlist.push(classes[i].innerText)
}
let lineclasses = classlist.join(", ")
val.onclick = function() {
jQuery.post('/cart/update.js', {updates: [lineclasses]});
console.log('dfdfdfd')
}
</script>
Here is my Liquid
{% for item in cart.items %}
<div class="product row">
<div class="col-lg-2 col-md-3 col-sm-4">
<img src="{{ item | img_url: 'medium' }}" />
</div>
<div class="col-lg-8 col-md-8 col-sm-7 product-info">
<div class="product-title">
{{ item.product.title }}
<span class="price right"><b>{{ item.price | money }}</b></span>
</div>
<div class="qty-select">
<input type="number" hidden="hidden" name="updates[]" id="updates_{{ item.key }}" class="qty"
value="{{ item.quantity }}" min="0" />
<span class="val">{{ item.quantity }}</span>
</div>
</div>
<div class="col-lg-2 col-md-1 col-sm-1 text-right remove">
<a aria-label="Remove {{ item.variant.title }}"
href="/cart/change?line={{ forloop.index }}&quantity=0"><i class="fas fa-times"></i></a>
</div>
</div>
{% endfor %}
I have tried this, but its not working