//  home   //  advanced search   //  news   //  categories   //  sql build chart   //  downloads   //  statistics
 ASP FAQ 
Home
ASP FAQ Tutorials

   8000XXXX Errors
   Alerts
   ASP.NET 2.0
   Classic ASP 1.0
      COM / ActiveX Components
      Forms
      General Topics
      Date/Time Routines
      Email Scripts & Info
      Files/Directories & FSO
   Databases
   General Concepts
   Search Engine Optimization (SEO)

Contact Us
Site Map

Search

Web
aspfaq.com
tutorials.aspfaq.com
classicasp.aspfaq.com

ASP FAQ Tutorials :: Classic ASP 1.0 :: Files/Directories & FSO :: How do I prevent people from 'leeching' my CSS or JS files?


How do I prevent people from 'leeching' my CSS or JS files?

I've heard a few people complain that external sites have linked to their CSS or JS files, which is both a waste of bandwidth and a potential copyright violation. Unfortunately, there is no straightforward way to prevent this from happening, and have fun trying to pursue it legally -- I was an expert witness in an Internet-related trial a few years ago, and it's amazing how much crap a lawyer can get away with it simply because the judge has no technical savvy whatsoever. 
 
In any case, there are ways to prevent people from borrowing these file types, and it's very similar to the method described in Article #2276, used to protect images from being swiped. 
 
The basic concept is that you serve up the CSS or JS from ASP, and the ASP page checks the referer to make sure it's on the same domain. So, for example, you can do this: 
 
<SCRIPT LANGUAGE=javascript SRC=js.asp></SCRIPT> 
<LINK REL=Stylesheet HREF=css.asp></SCRIPT>
 
Where js.asp may have the following code: 
 
<% 
    ref = lcase(request.serverVariables("HTTP_REFERER")) 
    if instr(ref,"localhost")>0 then 
        response.write "document.write('HELLO');" 
    end if 
%> 
 
And css.asp might look like this: 
 
<% 
    ref = lcase(request.serverVariables("HTTP_REFERER")) 
    if instr(ref,"localhost")>0 then 
        response.write "body { font-size:72pt }" 
    end if 
%> 
 
As with the images solution, note that this will be a bigger performance hit... and may affect how JS / CSS files are cached.

Related Articles

Can I include a file in both server-side and client-side script?
Can I read / write a user's file without a prompt?
Can I rename a file using FileSystemObject?
Could I get some help working with files using FileSystemObject?
How do I avoid 'the red x' when an image is missing?
How do I change the modified time of a file?
How do I create / manipulate images from ASP?
How do I dynamically include files?
How do I find the owner, author, and other properties of a file?
How do I get a list of a folder's subfolders?
How do I get the name of the current URL / page?
How do I prevent people from 'leeching' my images?
How do I retrieve a random file from a given folder?
How do I send the correct filename with BinaryWrite?
How do I sort a list of files?
How do I use FileSystemObject to create a file on the client?
Why do I get 'Disk not ready' errors with FileSystemObject?
Why do I get 'Invalid procedure call or argument'?
Why do I get 'Path not found' errors with Scripting.FileSystemObject?
Why do I get 'Permission Denied' errors with FileSystemObject?
Why do I get 800A0034 errors?
Why do I get 800A003E / Input past end of file errors?
Why do I get 800A0BBA errors?
Why do I get 800A0BBC errors?
Why do I get an 'Invalid Path Character' error?
Why do I get permissions errors after upgrading to Windows XP?
Why does FileSystemObject hang all of a sudden?
Why is 'the operation completed successfully' an error message?

 

 


Created: 4/15/2002 | Last Updated: 4/15/2002 | broken links | helpful | not helpful | statistics
© Copyright 2006, UBR, Inc. All Rights Reserved. (318)

 

Copyright 1999-2006, All rights reserved.
Finding content
Finding content.  An error has occured...