HTML element: Difference between revisions

Revision as of 01:33, 4 January 2024

Revision as of 21:37, 5 January 2024

Line 953:

{{Main|Framing (World Wide Web)}}

Frames allow a visual HTML browser window to be split into segments, each of which can show a different document. This can lower bandwidth use, as repeating parts of a layout can be used in one frame, while variable content is displayed in another. This may come at a certain usability cost, especially in non-visual user agents,<ref>{{cite web|url=http://www.washington.edu/doit/are-frames-accessible|title=Are frames accessible?|quote=...frames do present additional usability challenges that are unique to users with disabilities, particularly those who use screen readers.}}</ref> due to separate and independent documents (or websites) being displayed adjacent to each other and being allowed to interact with the same parent window. Because of this cost, frames (excluding the {{tag|iframe|o}} element) are only allowed in HTML 4.01 Frame-set. Iframes can also hold documents on different servers. In this case the interaction between windows is blocked by the browser. Sites like [[Facebook]] and [[Twitter]] use iframes to display content (plugins[[plugin]]s) on third party websites. Google [[AdSense]] uses iframes to display banners on third party websites.

In HTML 4.01, a document may contain a {{tag|head|o}} and a {{tag|body|o}} {{em|or}} a {{tag|head|o}} and a {{tag|frameset|o}}, but not both a {{tag|body|o}} and a {{tag|frameset|o}}. However, {{tag|iframe|o}} can be used in a normal document body.