Why we need to have two filters for lowercase/capital letters?

[smed79]

Hi,
for an adblocker i like to know what is the difference between two urls written in lowercase or capital letters?

for example this filters ##a[href^="http://www.FriendlyDuck.com/AF_"] found on easylist can't block banners link to: FriendlyDuck.Com/AF_

why we need to have two filters for just one lowercase/capital letter C?

##a[href^="http://www.FriendlyDuck.com/AF_"]
##a[href^="http://www.FriendlyDuck.Com/AF_"]

test: http://tinyurl.com/warez-world
Thanks!

[gorhill]

why we need to have two filters for just one lowercase/capital letter C?

Cosmetic filters must be valid CSS Selectors, and so are bound by the semantic of CSS Selectors. Attribute values are case-sensitive.

To not confuse with network filters, which are case-insensitive.

[gorhill]

By the way, you test case can be solved using a better filter:

###headerinfo-right-a

There can be only one id per element, so case sensitivity is not an issue when basing the cosmetic filter on the id.

Or you could also:

##a[href^="http://www.FriendlyDuck."]