Answer 1

您可以通过编写检查单选按钮值的自定义方法来执行此操作，并根据该值检查消息字段。这是您可以在jQuery中添加的代码

$.Validation.addRule("message",{
 check: function(value) {
    // Check the value of radio button here, You can do it as 
      if($("form input:radio:checked").val() == 'radio2') return true;
     // radio2 is checked then return valid, ie. this field is not required field.
    if(value.length > 0) {
        return true;
    }
    return false;
},
msg : "Field is required."
});