与对象无关的表单

form_tag

form_tag基本形态

#基本形态
<%= form_tag do %>
  Form contents
<% end %>

#生成的html样式，生成的两个hidden类型的属性
<form action="/" accept-charset="UTF-8" method="post">
  <input name="utf8" type="hidden" value="&#x2713;" />
  <input type="hidden" name="authenticity_token" value="MCllQOJYEuvoiBOM4uBnQKYpTAokXKJexm+oGghlQ7IS4G98lu32DobEdx5MuJ2ZcmHUKxIEngUxv3PKVlPigw==" />
  Form contents
</form>

form_tag示例

#form_tag示例
rails g scaffold tag name
#routes.rb
Rails.application.routes.draw do
  get '/tags/search', to: "tags#search"
  resources :tags do
    get 'search', on: :collection
  end
end
#models/tag.rb
class Tag < ApplicationRecord
  def self.search(arg)
    arg.strip!
    where(["name like ?", "%#{arg}%"])
  end
end
#controllers/tags_controller.rb
TagsController < ApplicationController
  def search
    @tags = Tag.search(params[:search])
    render 'index'
  end
end
#views/tags/index.html.erb
<%= form_tag "/tags/search", method: :get do %>
  <%= label_tag "tag" %>
  <%= text_field_tag :search %>
  <%= submit_tag "搜索" %>
<% end %>