How to get file extension in ruby and jquery

To get the file extension excluding the "." then do the following
@file_extension = file_name.split('.').pop()

To get the file extension along with "." then do the following
@file_extension = file_name.scan(/\.\w+$/)

Using Jquery
var ext = $('#file_field_id').val().split('.').pop().toLowerCase();

Access to /etc/hosts denied while modifying host file

This problem occurs when you  do not have the administrative rights.
You get an error when you try to edit the LMHOSTS or HOSTS file under Windows Vista.
Access to C:\WindowsSystem32\drivers\etc\ hosts was denied
or
Cannot create the C:\Windows\System32\drivers\etc\hosts file.
Make sure that the path and file name are correct.
To solve this problem:
1. Click Start–>All Programs–>Accessories–>Notepad–>Run as administrator.
If you are prompted for an administrator password or for a confirmation, type the password, or click Allow.
2. Open the Hosts file or the Lmhosts file, make the necessary changes, and then click Save on the Edit menu.

How to make dynamic on focus popup in the grid.

If you have a data table and need to display a on focus popup which shows the related columns content then you can do the following:
<% @objects.each do |object| %>
           
                   <%=h object.name%>                 
                  Show
                   

                                              <%if object.regions.nil?%>                                                   <%else%>                                                                                                                                                                 <%end%>                         <% object.regions.each do |region| %>                                                       <%if region.state.nil?                               state_name = ""                             else                               state_name = region.state.state_description                             end%>                                                         <%if region.super_region.nil?                               super_region_name = ""                             else                               super_region_name = region.super_region.super_region_description                             end%>                                                         <%if region.region.nil?                               region_name = ""                             else                               region_name = region.region.region_description                             end%>                                                                               <%end%>                      

No regions selected
State	Super Region	Region
<%= state_name %>	<%= super_region_name %>	<%= region_name %>

                   

                       
           
<% end %>
<% end %>