Warning on leaving a page with unsaved content in textarea (#2910).

The warning can be turned off in the user's preference.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@4900 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/views/layouts/base.rhtml

@@ -8,7 +8,7 @@
 <%= favicon %>
 <%= stylesheet_link_tag 'application', :media => 'all' %>
 <%= stylesheet_link_tag 'rtl', :media => 'all' if l(:direction) == 'rtl' %>
-<%= javascript_include_tag :defaults %>
+<%= javascript_heads %>
 <%= heads_for_theme %>
 <%= heads_for_wiki_formatter %>
 <!--[if IE 6]>