Product page - Add extra data to submit form add to cart

I created a theme extensions which added selectboxes to the product detail page with options a customer can choose from.

Now when a user clicks on the add to cart button, I want to validate if they have filled in all selectboxes. How can I do this.

A second thing I want to do is show these chosen options in the checkout. How can I do this.

I google a lot, went trough shopify’s documentation but it is not clear to me how I can implement this.

Help!

Hello @FraukeFvdz ,

If atc is using ajax then you have to write a script to validate the values.
If not then simply follow this https://ui-elements-generator.myshopify.com/pages/line-item-property you can find all details here.

Thanks