some Rails leanrning:Rails Ajax,Validates,Cycle

how to name the table、rails class
your mysql database need a table named my_stories,note that:not mystories,not my_story,and mapping class should named MyStory.

Rails Ajax
it's very simple using Ajax on rails web application.
1.using link_to_remote
<head>
<%=javascript_include_tag "prototype"%>
</head>
<%= link_to_remote( "click here",
                   :update => "time_div",
                   :url => { :action => :say_when },
                   :position => "after" ) %>
<div id="time_div">
2.using form_remote_tag
<head>
<%=javascript_include_tag "prototype"%>
</head>
    <%= form_remote_tag(:update => "my_list",
                       :url => { :action => :add_item },
                       :position => "top" ) %>
      New item text:
      <%= text_field_tag :newitem %>
      <%= submit_tag "Add item with Ajax" %>
    <%= end_form_tag %>
<ul id="my_list"></ul>
3.using Observers
Make an Ajax call to an action handler whenever the value of the field changes.
<head>
<%=javascript_include_tag "prototype"%>
</head>
Live search:<%=text_field_tag :searchtext%>
       <%=observe_field(:searchtext,
                        :frequency=>0.25,
                        :update=>:search_hits,
                        :with => "searchtext",
                        :url=>{:action=>:live_search})%>
        <p>Search Results :</p>
        <div id="search_hits"></div>

Validation

in model class just add like this
validates_presence_of :title,:image_url
validates_numericality_of :price
validates_uniquenss_of:title
validates_format_of:imageurl,
 :with => %r{^http:.+\.(gif|jpg|png)$}i,
 :message=>"must be a URL for a GIF,JPG,or PNG image"

Cycle
for product in @products
end

@products.each do |product|
end

原文地址:https://www.cnblogs.com/caca/p/430018.html