Javascript onfocusout使用jQuery验证某些特定字段

我正在使用jQuery验证插件来验证我的表单。我的表格中有一对出发地和目的地城市以及一对开始日期和结束日期。我希望

onfocusout

功能仅在机场字段中工作，因为它们在这两个字段中都有相同的代码

下面是我的代码

$(function () {
    var validator = $("#testForm").validate({
        errorClass: "errorMsg",
        errorElement: "span",
        rules: {
            fromAirport: {
                "required": true,
                "onfocusout": true
            },
            toAirport: {
                "required": true,
                "onfocusout": true
            },
            fromDate: {
                "required": true,
                "onfocusout": false
            }
            toDate: {
                "required": true,
                "onfocusout": false
            }
        },
        messages: {
            fromAirport: {
                "required": "fromAirportis required!"
            },
            toAirport: {
                "required": "toAirportis required!"
            }
            fromDate: {
                "required": "fromDateis required!"
            },
            toDate: {
                "required": "toDate is required!"
            },
        },
        onfocusout: function(el) {
            if (!this.checkable(el)){
                this.element(el);
            }
        },
        submitHandler: function (form) {
        }
    });
});

jsFiddle:

关于此代码

onfocusout: function(el) {
    if (!this.checkable(el)){
        this.element(el);
    }
},

rules: {
    fromAirport: {
        "required": true,
        "onfocusout": true // <- No such rule
    }, ...

什么是可检查的？有

关于此代码

onfocusout: function(el) {
    if (!this.checkable(el)){
        this.element(el);
    }
},

rules: {
    fromAirport: {
        "required": true,
        "onfocusout": true // <- No such rule
    }, ...

---

演示：

你能创建一个

演示吗？同意！很好的解决方案。