我不明白这个输出。我有这个
<%= link_to(:class=>"dropdown-toggle", "data-toggle"=> "dropdown") do %>
<%= content_tag(:span, :class=>"hidden-xs-only") do %>
<%= link_to("Sign Up", new_user_registration_path) %>
<% end %>
<% end%>
但它输出这个
<a class="dropdown-toggle" data-toggle="dropdown">
<span class="hidden-xs-only">
</span>
</a>
<a href="/users/sign_up">Sign Up</a>