This method may or may not be the best for your site. Just learn what you can, and go from there.Let's say you want to have your main page content a certain width. Of course, you could use frames or tables and simply specify the width in pixels.But what if you want it centered in the middle of the page with equal "Margins" on both sides, no matter at what size the user's screen is set?Then your content will be in a window of a specific size in the middle of the screen.