[gregwk]

I have used the suggested technique to block flash files -- placing /.swf$ in the blocked URL list. However, when I load www.lynda.com there is a flash file that continues to play (actually there are two, but only one is annoying). Does anyone else get this same behavior and is there any way to stop it?

BTW, Flashblock on Firefox handles them appropriately.

Thanks,
Greg

[gregwk]

I put /.swf instead of /.swf$ in the blocked URL list and everything worked fine.

gwk

[troyb]

adding the '$' at the end says "only match this if it's at the end of a line. Without the $ it will match anywhere in the line.

[zottel]

/.swf will not block so much, with $ at the end or without: The . will matach any character, but the / will only match /. So this line will only block URLs that contain strings like '/aswf' or '/Xswf', which aren't very widespread. ;-)

If you want to block flash, the best thing will be to look for URLs with 'swf' at the end of the line. The corresponding line would be:

swf$

What you have seen is probably the hint to use the line

/.*swf$

or similar to block flash. This means: A /, then any character (.), zero or multiple times (*), then 'swf' at the end of the line ($). As slashes tend to occur in about any URL (at least twice at the end of 'http://'), this works, too, but it is unnecessarily complicated. I don't know why many people seem to use the slash at the beginning—probably because we're used to using slashes with regular expressions (in many programming languages, regular expressions are encircled with slashes).

If you want to know more about ad blocking with regular expressions, you might want to read this: http://forums.omnigroup.com/showthread.php?t=2036

[troyb]

Oops, I missed that a "/" is getting used instead of "\". The example provided in help is "\.swf$". The backwards slash prevents the next character from doing anything special so a period matches just a period. Not any character. All this makes the expression match .swf at the end of a line.

If i block flash, personally I just use "swf" without the quotes. This grabs pretty much all flash regardless of whether the match shows up in the middle of the line or the end and doesn't look for the preceding period which is usually there but not always.