How to dynamically control text_field property in rails form

Question

I would like to set a rails form text_field property to read only when the model already contains a value.

Here is my code

<%= f.text_field :domain, class="span4", readonly: "true" %>

I want to avoid doing something verbose like:

<%if @model.domain.empty? %>
   <%= f.text_field :domain, class="span4"%>
<%else%>
   <%= f.text_field :domain, class="span4", readonly: "true" %>
<%end%>

Thanks!

Answer 1

<%= f.text_field :domain, class="span4", :disabled => !@model.domain.blank? %>