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/helpers/application_helper.rb

@@ -894,6 +894,15 @@ module ApplicationHelper
       ''
     end
   end
+  
+  # Returns the javascript tags that are included in the html layout head
+  def javascript_heads
+    tags = javascript_include_tag(:defaults)
+    unless User.current.pref.warn_on_leaving_unsaved == '0'
+      tags << "\n" + javascript_tag("Event.observe(window, 'load', function(){ new WarnLeavingUnsaved('#{escape_javascript( l(:text_warn_on_leaving_unsaved) )}'); });")
+    end
+    tags
+  end
 
   def favicon
     "<link rel='shortcut icon' href='#{image_path('/favicon.ico')}' />"