jquery验证,当输入字段具有title属性时,而不是错误消息标题作为错误消息给出

$(document).ready(function() {
    $('#form').validate({
        rules: {
            field1: {
                required: true,
                minlength: 5
            },
            field2: {
                required: true,
                email: true
            }
        },
        messages: {
            field1: {
                required: "请输入字段1的内容",
                minlength: "字段1的内容至少要有5个字符"
            },
            field2: {
                required: "请输入字段2的内容",
                email: "字段2的内容必须是有效的电子邮件地址"
            }
        },
        errorPlacement: function(error, element) {
            if (element.attr("title")) {
                error.insertAfter(element.closest("legend"));
            } else {
                error.insertAfter(element);
            }
        }
    });
});