any good testing tool for web app?

I am testing web app and I hope you guys can give me recommandation on web testing tool.
Preferably free ware or cheap, easy to use, flexible to update as applicaiton evolves...
Thanks in advance.

Which aspects would you like to test? For example, there is Cactus for unit testing servlets, jsp and tags, TagUnit for unit testing JSP tags, HttpUnit for functional testing the actual website and so on. Basically, there are many different tools depending on what you want to test. Here's a list of JUnit web extensions to get you started.

I am looking for a tool to record functionalities of web app ( creating items, clicking some tabs ....) as black box testing. But I do not want tools record by the position.

Looks like you want to do some functional testing. So, as Simon suggested, HttpUnit will probably work well for you.

Originally posted by Sue Pag:
I am looking for a tool to record functionalities of web app ( creating items, clicking some tabs ....) as black box testing. But I do not want tools record by the position.

What do you mean by "record by the position"? You don't want the test scripts to hard code the absolute URLs?
If you're a money man (i.e. the customer has big pockets), you could try Mercury Interactive's LoadRunner. It can record user behavior from Internet Explorer and produces a test script written in C/Java (many others available). Afterwards you can edit this C/Java source by adding looping, parameterization, etc. The links in the scripts are based on link names, not URLs. The first page load however needs to be parameterized afterwards to suit your "not by the position" requirement.

You could also take a look at http://fitnesse.org/FitNesse.WebAcceptanceTestingTool

I wrote an automation testing tool, Jameleon that currently has an HTTP plugin supplied.
So far it has worked very well for us!