Match validation

if (no_error && elem.name == 'email') {
           var domain = value.match(/@([a-zA-Z0-9._-]+)$/)?.[1];
            if (!value.match(/^[\+_a-z0-9-'&=]+(\.[\+_a-z0-9-']+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,})$/i)) {
                elem.className = elem.className + ' _has_error';
                no_error = false;
                tooltip = create_tooltip(elem, "Enter a valid email address.");
            } else if(invalidEmailDomains.includes(domain)){
                elem.className = elem.className + ' _has_error';
                no_error = false;
                tooltip = create_tooltip(elem, "Enter a business email address.");
            }
}