问题描述
举个例子，在表单中有这样的内容：
<dl> <dt><%= f.label :subject %> </dt> <dd><%= f.text_field :subject %> </dd> </dl>
在浏览器中显示成：
■Subject
(※注：■由CSS生成)
如果对表单进行验证，验证后再显示的格式就乱了，变成这样：
■Subject
为什么会错位呢？
问题解答
回答1：You should override ActionView::Base.field_error_proc. It’s currently defined as this within ActionView::Base:
@@field_error_proc = Proc.new{ |html_tag, instance| '<p class='field_with_errors'>#{html_tag}</p>'.html_safe }
You can override it by putting this in your application’s class inside config/application.rb:
config.action_view.field_error_proc = Proc.new { |html_tag, instance| '#{html_tag}'.html_safe }
Restart rails server for this change to take effect.
（全文抄袭自 http://stackoverflow.com/questions/5267998/rails-3-field-with-errors-wrapper-changes-the-page-appearance-how-to-avoid-t）
当然，更推荐改成这样
config.action_view.field_error_proc = Proc.new do |html_tag, instance| class_attr_index = html_tag.index ’class=’ if class_attr_index html_tag.insert class_attr_index+7, ’error ’ else html_tag.insert html_tag.index(’>’), ’ class='error'’ endend
