Hi tullio0106,
If you want to get the value of the smart-checkbox I have a code snippet made with the demo I send you in my previous reply:

 let checkBox = document.getElementById('checkBox');
 checkBox.addEventListener('change', (event) => {
        console.log(event.detail.value)
    })

Please, do not hesitate to contact us if you have any additional questions.
Best regards,
Yavor Dashev
Smart UI Team
https://www.htmlelements.com/