framesets

Framesets are a web design construct used to divide a browser window into multiple, independently scrollable panels, each loading a separate HTML document. They were part of HTML 4.01 and rely on the frameset element instead of a body to define the layout. A frameset can arrange its child frames in horizontal rows or vertical columns.

The structure is defined by a frameset element that uses the cols or rows attributes to specify the partition. Each frame element within the frameset points to a separate source document via the src attribute and can have its own name, scrolling behavior, and other properties. Nested framesets allow more complex layouts. For example, a typical layout might be a narrow navigation frame alongside a larger content frame. A noframes element can provide alternative content for browsers that do not support frames.

Framesets create multiple documents within a single window, so the document that contains the frameset has no body content of its own. If a browser does not support frames, the noframes section can offer a fallback. In practice, framesets introduced several usability and accessibility challenges.

Today, framesets are considered obsolete in modern web development. HTML5 deprecated frames and framesets, and most developers advocate CSS-based layouts using divs, along with responsive techniques like flexbox and grid. When embedding external content, iframes remain useful, but they are not a replacement for a multi-frame layout. For many sites, transition involves reworking navigation and content into a single, cohesive document architecture with accessible, responsive design.