Many characteristics of the simulated browser can be set by the user:

First, you need to note that Webserver Stress Tool simulates a browser only from a “server’s point of view” (e.g., sending the requests, etc.), but does not simulate the rendering on the client’s screen or the execution of client side scripts. Thus Java applets, Javascripts etc. are not executed (running scripts of many users would also put excessive load on the client's CPU).
For example a scripted inclusion of a banner ad is not processed and thus the image request is not sent to the server. The implication is that the performance effect of such client side portions of the web application cannot be measured by this webserver loading/stressing technology.
Also any requests that are generated through Javascripts will also not be processed, use the Custom URL Script to add the these URLs manually.
Webserver Stress Tool is a powerful HTTP-client/server test application designed to pinpoint critical performance issues in your web site or web server that may prevent optimal experience for your site's visitors.
Welcome
Introduction: Testing Basics
Performance, Load or Stress Testing?
Calculation of Load and Load Pattern
Webserver Stress Tool Features
How much load can Webserver Stress Tool generate?
Installation
Configuring Webserver Stress Tool
Selecting the Test Type and the Number of Users
Selecting the URLs or Editing the URL Script
Using Custom URL Scripts for Advanced URL Sequences
Performance Tips&Tricks
Running the Test
Reviewing Logfile Results
Analyzing Graphical Results
Graph Click Times & Errors (per URL)
Graph Click Times, Hits/s and Clicks/s
Graph Server and User Bandwidth
Creating Reports
Additional Features
Appendix
Software License and Contact Information