What it does:
Webserver Stress Tool simulates lots of users by sending http-requests to a webserver. It works with almost any server based technology like asp, jsp, cfm, or java. Many different load patterns can be generated with this web testing tool.
What it does not:
This web testing tool does not simulate the client based processes (e.g. javascripts or java applets running inside the webbrowser). It simulates the HTTP requests (for webpages, HTML, images, frames, etc.) sent by a computer a user uses to access a website.
Nevertheless websites using JavaScript/Java can usually be tested. Since most client side scripts create nothing else but HTTP requests, it is still possible to test such web sites. You can record the URLs using the included URL recorder for the test or you can write your own script with the URLs to test.