Sorry, but this isn't a HTML or CSS help site. Furthermore, if you were looking for a Perl solution, you're outta luck since most clients are unable to execute Perl scripts. CGI scripts run on the server, so they don't have access to the information needed to determine the position of content on the client machine's window. (JavaScript might...)

I must wonder why you are asking how to use *absolute* positioning to place an item *relative* to another. Is CSS that limited or CSS support that broken?

I think you are going wrong way.

Different windows could't have different resolutions. Or maybe you're talking about different clients?

And i'm sure there is the way to achieve this behavior -- CSS

I believe he meant different sizes.

Notice how the position of the key item changes in the following two "browser windows":

foo foo foo foo foo keyword foo foo foo

foo foo foo foo foo keyword foo foo foo

So to use your example the arrow is attached to the "keyword" but because of formatting the word position changes with window size.
Then perhaps one way would be to combine text and "arrow pointer" into an image and display that in the browser