function success(e) {
    e.preventDefault();
    var phone = document.getElementById("tel");
    var term = phone.value;
    var re = new RegExp("^((\+7|7|8)+([0-9]){10})$");
    if (phone.value != '' && re.test(term) == true) {
        Swal.fire(
            'Good job!',
            'You clicked the button!',
            'success'
        );
    }else{
        Swal.fire(
            'Good job!',
            'You clicked the button!',
            'error'
        );
    }
}