function onChange(control, oldValue, newValue, isLoading) {
    if (isLoading || newValue == '') {
        return;
    }

    //Type appropriate comment here, and begin script below
    var pattern = /^[(]?(\d{3})[)]?[-|\s]?(\d{3})[-|\s]?(\d{4})$/;

    if (!pattern.test(newValue)) {
        alert('Phone enter a valid phone number');
        g_form.setValue('variable_name', '');
    }
}