Blocking Macromedia flash based ads
 

How does one go about blocking MacroMedia flash based ads?

If you put the mouse pointer over one of those ad types, you don't see a URL in the status bar to base your ad block expression on. If you CTRL click on the ad, you see a menu showing 'Settings' and 'about Macromedia FlashPlayer'.

Any suggestions? What would I look for in the source. Anything in particular?

Flash URLs normally end with ".swf", so just put the following in your blocked URLs list:

\.swf$

(Explanation: "." means "any char" in regular expressions, so you have to escape the "." with the backslash. "$" means "end of string".)

Ok. Thanks.

I already picked that part up in the help while waiting for suggestions. :)

I was hoping for a more selective method rather than one that blocks them wholesale.

What do you mean by "more selective"?

You can, of course, always use that template to only block flash ads from a certain server. E.g.: To only block flash from the server some.ad.com, use

some\.ad\.com.*\.swf$

(Explanation: Matches on any URL that contains "some.ad.com" ('.'s have to be escaped), followed by zero or more chars (".*"), followed by ".swf" at the end of the string.)

Or, just to show the power of regular expressions: ;-) If you only want to block flash files that contain "ad" in their filename, you could use:

ad[^/]*\.swf$

That means: Match anything that contains "ad" followed by a char that is not '/' ('[^/]') zero or more times ('*'), followed by ".swf" at the end of the string. You only match the filename itself, since the rest of the URL would contain a '/'. ([] is a character group. [abc] means: "One of the chars a, b, or c." Inside [], '^' means "not". So if you want to match any char that isn't '/', you can use [^/]. That itself would mean "one char that isn't '/'". An '*' means "the item before the '*', zero or more times". "a*" means "zero or more 'a's". "[dgy]*" means "zero or more times a 'd', a 'g', or a 'y'". As '.' means "any char", ".*" means "zero or more times any char". And "[^/]*" means "zero or more times any char, but not '/'".)

FWIW, I just block images from third-party sites as a whole. Then use the site prefs to disable that block on sites where it doesn't work well. That nails almost all the Flash ads I would normally run across.

Thanks Forrest and Zottel.

Zottel, I'm pretty familiar with regular expressions and was finding my way. I had not used them in a while so you reminded me how to match a everything except a particular character. :) I have created quite a few expressions already.

Forrest, it seems to be a matter of which setup has you doing less selective blocking/allowing on a per-site basis.