Rails 中的动态选择菜单？

Question

我正在尝试让动态选择菜单在我的 Rails 应用程序中工作。

我有一个名为 kase 的模型，一个名为 person 的模型和一个名为 company 的模型。

当用户创建新的 kase 时，他们会看到一个用于选择人员的选择字段和一个用于选择公司的选择字段。

我试图使其动态化，因此如果他们在第一个选择字段中选择公司 a，则只有公司 a 的员工才会在人员字段中列出。

模型关联如下：

class Kase < ActiveRecord::Base

  belongs_to :company # foreign key: company_id
  belongs_to :person # foreign key in join table
  belongs_to :surveyor,
             :class_name => "Company",
             :foreign_key => "appointedsurveyor_id"
  belongs_to :surveyorperson,
             :class_name => "Person",
             :foreign_key => "surveyorperson_id"

-------------------------------------------------  

class Company < ActiveRecord::Base
  has_many :kases
  has_many :people
  def to_s; companyname; end

-------------------------------------------------

class Person < ActiveRecord::Base
  has_many :kases # foreign key in join table
  belongs_to :company

更新的 JAVASCRIPT

var people = new Array();
<% for person in @people -%>
  people.push(new Array(<%= person.company_id %>, '<%=h person.personname %>', <%= person.id %>));
<% end -%>

function personSelected() {
  alert('hello world');
  appointedsurveyor_id = $('kase_appointedsurveyor_id').getValue();
  options = $('kase_surveyorperson_id').options;
  options.length = 1;
  people.each(function(person) {
    if (person[0] == appointedsurveyor_id) {
      options[options.length] = new Option(person[0], person[1]);
      alert('hello world')
    }
  });
  if (options.length == 1) {
    $('kase_surveyorperson_id').hide();
  } else {
    $('kase_surveyorperson_id').show();
  }
}

document.observe('dom:loaded', function() {
  $('kase_appointedsurveyor_id').observe('change', personSelected);
});

Answer 1

var people = new Array();
<% for person in @people -%>
  people.push(new Array(<%= person.id %>, '<%=h person.login %>'));
<% end -%>

function personSelected() {
  alert('hello world');
  appointedsurveyor_id = $('company_appointedsurveyor_id').getValue();
  options = $('person_appointedsurveyorperson_id').options;
  options.length = 1;
  people.each(function(person) {
    if (person[0] == appointedsurveyor_id) {
      options[options.length] = new Option(person[0], person[1]);
    }
  });
  if (options.length == 1) {
    $('person_field').hide();
  } else {
    $('person_field').show();
  }
}

document.observe('dom:loaded', function() {
  //companySelected(); << remove this
  $('person_field').observe('change', personSelected);
});

Answer 2

尝试观察字段。 http://api.rubyonrails.org/classes/ActionView/Helpers/ PrototypeHelper.html#M002183