Rails -依次填充类别和子类别的选择菜单

Question

我正在尝试在我的Rails4应用程序中创建一个表单，它有两个选择标记。一个用于类别，另一个用于子类别。我希望子类别中的选项由类别的选择决定。

目前我有这样的表格：

<div class="nested-fields">
<div class="container-fluid">

  <div class="form-inputs">

    <%= f.input :irrelevant, :as => :boolean, :label =>  "Is an ethics review required or applicable to this project?"  %>

    <%= f.input :category, collection: [ "Risk of harm", "Informed consent", "Anonymity and Confidentiality", "Deceptive practices", "Right to withdraw"], :label => "Principle",  prompt: 'select' %>

    <%= f.input :subcategory,  collection: text_for_subcategory(@category), :label => "Subcategory", prompt: 'select'  %>



    </div>
  </div>
  </div>

我还有一个助手：

module EthicsHelper
    def text_for_subcategory(category)
      if category == 'Risk of harm'
            [ "Physical Harm", "Psychological distress or discomfort", "Social disadvantage", "Harm to participants", "Financial status", "Privacy"]
        elsif category == 'Informed consent'
            ["Explanation of research", "Explanation of participant's role in research"]
        elsif category == 'Anonymity and Confidentiality'
            ["Remove identifiers", "Use proxies", "Disclosure for limited purposes"]
        elsif category == 'Deceptive practices' 
            ["Feasibility"] 
        else category == 'Right to withdraw'    
            ["Right to withdraw from participation in the project"] 
       end
    end  

end

当我尝试这样做时，不管我在category字段中做了什么选择，subcategory字段都只填充了最后一个属性(right the )。

我在上面所做的事情有些不对劲，我不知道是什么。

有人能看到我哪里出错了吗？

Answer 1

向选择字段添加类：

<%= f.input :category, collection: [ "Risk of harm", "Informed consent", "Anonymity and Confidentiality", "Deceptive practices", "Right to withdraw"], :label => "Principle",  prompt: 'select', class: "main_category" %>

<%= f.input :subcategory,  collection: text_for_subcategory(@category), :label => "Subcategory", prompt: 'select', class: "sub_category" %>

添加以下javascript代码。

$(document).ready(function() {
  $(".main_category").change(function(){
    var category = $(".main_category").val(),
        sub_category = $(".sub_category"),
        options = [],
        str = "";
    sub_category.find('option').remove();

    if(category == 'Risk of harm'){
      options = ["Physical Harm", "Psychological distress or discomfort", "Social disadvantage", "Harm to participants", "Financial status", "Privacy"]
    }
    else if(category == 'Informed consent'){
      options = ["Explanation of research", "Explanation of participant's role in research"]   
    }
    else if(category == 'Anonymity and Confidentiality'){
      options = ["Remove identifiers", "Use proxies", "Disclosure for limited purposes"]
    }
    else if(category == 'Deceptive practices'){
      options = ["Feasibility"]
    }
    else if(category == 'Right to withdraw'){
      options = ["Right to withdraw from participation in the project"]  
    }
    if(options.length > 0){
      for(i=0;i<options.length;i++){
        str = '<option value="' + options[i] + '">' + options[i] + '</option>'
        sub_category.append(str);
      }
      sub_category.val(options[0]);
    }
  });
});

我还没有测试代码。