The web browser application on my Samsung Droid Charge has a Brightness Setting that can be accessed from the menu button while the browser is running. There is no setting to have the browser automatically use the same brightness setting as the phone, or use auto brightness. I have no idea why Samsung put in this setting without a way to turn it off! Is there a way to work around this?
Samsung with its quest to be different, enriched the stock browser, with its own brightness control, totally separate from the OS.
There's no workaround, you have to set the brightness independently.
Even using an app to control the brightness levels, as soon as you launch the stock browser, its own brightness control overwrites the one from the app.
If you have root on your device, you can replace the browser
There are alternative solutions for this, like many other users faced with your problem endup using, the usage of another browser that's not the stock one.