如何在jquery验证中添加条件

Question

我在表格上有一些验证。我想补充一些其他验证。在firstname textfield中只允许使用字母文本。

在此jquery中仅为字母添加哪个关键字。

以下是验证表单的代码。

$("#validateForm").validate({
    debug: false,
    rules: {
        firstname: {
            required: true,
            maxlength: 10
        },
        lastname: {
            required: true,
            maxlength: 10
        },
        contactmail: {
            required: true,
            email: true
        },
        jobtitle: "required",
        username: {
            required: true,
            minlength: 2
        },
        password: {
            required: true,
            minlength: 5
        },
        repassword: {
            required: true,
            minlength: 5,
            equalTo: "#password"
        }

    },
    messages: {
        firstname: {
            required: "Please enter your firstname",
            maxlength: "firstname must consist of below 10 characters"
        },
        lastname: {
            required: "Please enter your lastname",
            maxlength: "lastname must consist of below 10 characters"
        },
        contactmail: {
            required: "Please enter email address",
            email: "Email must be in the format of name@domain.com"
        },
        jobtitle: "Please enter job title",
        username: {
            required: "Please enter a username",
            minlength: "Your username must consist of at least 2 characters"
        },
        password: {
            required: "Please provide a password",
            minlength: "Your password must be at least 5 characters long"
        },
        repassword: {
            required: "Please provide a retype password",
            minlength: "Your password must be at least 5 characters long",
            equalTo: "Please enter the same password as above"
        }

    },
});