Using the default rails field_error_proc may lead to some layout headaches–your form looks perfect until, uh-oh, someone entered an invalid email address and Rails adds a fieldWithError-styled div that wraps around the problem field.

While this works in many cases, some pixel-perfect layouts may not be able to tolerate the 2-pixel padding around the text_field caused by the red border. An alternative is to change the background color of the offending field.

Include the following code in environment.rb (or use a “require” like I do):

ActionView::Base.field_error_proc = Proc.new do |html_tag, instance|
  error_style = "background-color: #ffff80"
  if html_tag =~ /<(input|textarea|select)[^>] style=/
    style_attribute = html_tag =~ /style=['"]/
    html_tag.insert(style_attribute   7, "#{error_style} ")
  elsif html_tag =~ /<(input|textarea|select)/
    first_whitespace = html_tag =~ /\s/
    html_tag[first_whitespace] = " style='#{error_style}' "
  end
  html_tag
end

Update: Removed some “cruft left over from refactoring”

Update #2: Here is a CSS-friendly version (Thanks to Technoweenie for the suggestion):

ActionView::Base.field_error_proc = Proc.new do |html_tag, instance|
  error_class = "field_with_error"
  if html_tag =~ /<(input|textarea|select)[^>] class=/i
    class_attribute = html_tag =~ /class=['"]/i
    html_tag.insert(class_attribute   7, "#{error_class} ")
  elsif html_tag =~ /<(input|textarea|select)/i
    first_whitespace = html_tag =~ /\s/
    html_tag[first_whitespace] = %{ class="#{error_class}" }
  end
  html_tag
end

In January of this year, James Lovelock, author of the Gaia Theory announced that the earth has caught a fever manifest by irreversible global warming.

More recently, the BBC released an article confirming the alarming rate of increase of CO2 in the atmosphere.

And now there is evidence that not only have our American governing officials been aware of it, but they have actively been censoring communication from those who can help us most. More information on this censorship here.

Awareness is increasing.