Is this from a database that is published to the web (IWP or CWP)?
Or do you want to launch a web browser and view the web page from a button clicked by someone directly using FMP?
Yes, that's right -I want to launch a web browser and view the web page from a button.
If I understand you correctly, then all you have to do is store the URL in a field as then use Open URL
Have you looked into using FMP's Web Viewer? You can use this to set up a layout with a "web browser" window and use a URL stored in a field to control which web site is visible in the web viewer.
For more on web viewers, check out fmp's help file.