You can't in HTML...

Subject: You can't in HTML...
Name: SickOfItAll
Date: 8/13/2001 1:38:04 PM (GMT-7)
IP Address: 208.1.79.30
In Reply to: Hyperlinks posted by ToXiK
Message:

It requires a script in something like PHP or ASP to return a MIME header that tells the browser not to open the file. From what I've been reading, it is a very pesky issue, and none of the solutions seem to work across the board in all browsers.

So unless you are developing on a platform that supports Server Side scripting, and know how to write some clever header-modifiers, your best bet is to go with the .ZIP file suggested by tide.

Here is an example you can reference if you are interested in scripting it:

PHP example