modifying the url from within a user-defined tag

[ignace]

Hey,

I have created a user-defined tag and a new content page calling my user-defined tag, without any parameters. The user-defined tag is a project browser it display's an image and a little text beneath the image. On the image are there a previous and a next button, so i need to be able to manipulate the url so the tag is able to create the next and previous url's

thanks for any help

[aln_cms]

you're going to need a parameter I think, it will indicate the current project_id - giving you a starting point for your previous and next links.  If it is embedded in the params, $_GET or pagedata yo may be able to avoid the parameter and source it from there.

[ignace]

I am well aware on how to retrieve information from the url! That wasn't also my question, the question is how can i modify the current url so that it points to my next and previous projects?

I probably can't.. but no problem i'm using a module already instead

[aln_cms]

I am well aware on how to retrieve information from the url! 

That wasn't so clear in your initial post.