Frames are made up of two major components—a frameset and individual frames. A frameset is an HTML page that defines the structure of a set of frames within a document. The frameset definition includes information about the number of frames displayed on a page, the size of the frames, the source of the page loaded into a frame, and other definable properties. A frameset HTML page isn't displayed in a browser; it simply stores information about how the frames on a page will display.
HTML frames are spatially defined regions or areas in an HTML page. Each frame in a page "holds" an individual HTML document. In a Web page, frames commonly define a navigation area and a content area for a page.
When you split a Dreamweaver document into frames, you create separate HTML documents for the frameset and for each new frame. The frameset is referred to as a parent frame, and a frame is referred to as a child frame.
You can create new content directly in a frame page, link existing pages to open in a frame, and set up a behavior to change content in multiple frames.
What a user sees as a single Web page with two frames is actually three separate files: the frameset file and two files containing the content that appears inside the frames.
Changing the properties of frames and framesets allows you to resize frames and to use links and targets to control a frame's contents.
When View > Frame Borders is off, the frameset appears exactly as it does in a browser. When frame borders are displayed, Dreamweaver adds space around the document for the border and widens small borders. This makes it easier for you to drag and select a frame.