This question already has an answer here:
Block comments in html.erb templates in rails
ruby on rails notes has a very nice blogpost about commenting in erb-files
the short version is
to comment a single line use
<%-# commented line -%>
to comment a whole block use a
if false to surrond your code like this
<% if false %> code to comment <% end %>
Note that if you want to comment out a single line of printing erb you should do like this
<%#= ["Buck", "Papandreou"].join(" you ") %>
The below also happens to answer the Original Poster's question without, the "ugly" conditional code that some commenters have mentioned.
CONTIGUOUS NON-PRINTING Ruby Code
This will work in any mixed language Rails View file, e.g,
*.html.erb, *.js.erb, *.rhtml, etc.
This should also work with STD OUT/printing code, e.g.
<%#= f.label :title %>
Rather than use rails brackets on each line and commenting in front of each starting bracket as we usually do like this:
<%# if flash[:myErrors] %> <%# if flash[:myErrors].any? %> <%# if @post.id.nil? %> <%# if @myPost!=-1 %> <%# @post = @myPost %> <%# else %> <%# @post = Post.new %> <%# end %> <%# end %> <%# end %> <%# end %>
YOU CAN INSTEAD add only one comment (hashmark/poundsign) to the first open Rails bracket if you write your code as one large block... LIKE THIS:
<%# if flash[:myErrors] then if flash[:myErrors].any? then if @post.id.nil? then if @myPost!=-1 then @post = @myPost else @post = Post.new end end end end %>