Dynamic Validation

function validate() {
    var reg = /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
    const inputField = document.getElementById('email');
    inputField.addEventListener('input', function(){
        if(reg.test(inputField.value)){
            inputField.classList.remove('error');

                }else{
                    inputField.classList.add('error');
                }
    });
}