In the context of a web browser, a frame is a part of a web page or browser window which displays content independent of its container, with the ability to load content independently. The HTML or media elements that go in a frame may or may not come from the same web site as the other elements of content on display. In HTML, a frameset is a group of named frames to which web pages and media can be directed; an iframe provides for a frame to be placed inside the body of a document. Since the early 2000s, the use of framesets has increasingly been considered obsolete due to usability and accessibility concerns, and the feature has been removed from the HTML5 standard.
The HTML 4.0 standard included two different forms of frame,
frame element, used inside a special
frameset container, and the
iframe element, used within the body of a document.
In HTML 4.01, a document, which would normally contain a
head and a
body, may instead contain a
head and a
frameset (but not both a
body and a
frameset). The attributes
cols on the opening
frameset tag define the dimensions of a grid of frames using comma-separated lists of sizes, specified in either pixels or percentages. Any row or column size may be replaced with an asterisk to indicate the remainder of the remaining screen space. Within the
frameset, a series of
frame elements describe the initial source documents for each frame in the frameset, as well as assigning them names for use as the target of links. The
<noframes> element may be included so web browsers with frames disabled (or browsers that do not support frames) can display something to the user, as in this example:
<frameset cols="85%, 15%"> <frame src="http://www.example.com/frame_1.html" name="frame_1"> <frame src="http://alt.example.com/frame_2.html" name="frame_2"> <noframes> Text to be displayed in browsers that do not support frames </noframes> </frameset>
iframe element is used inline within a normal HTML body, and defines the initial content and name similarly to the
Netscape Navigator 2.0 introduced the elements used for frames in March 1996. Other browser vendors such as Apple with Cyberdog followed later that year. At that time, Netscape proposed frames to the World Wide Web Consortium (W3C) for inclusion in the HTML 3.0 standard.
Frames were used to display and navigate early web apps, such as web chat sites and online magazines. Frames had the advantage of allowing elements to be displayed sitewide without requiring server features such as server-side includes or CGI support. These features were not common on early web servers accessible to the public.
Early websites often used a frame at the top to display a banner which could not be scrolled away. These banner frames sometimes included the site's logo as well as advertising.
XHTML, intended as a successor to HTML 4, removed all frames in 1.1. The intended eventual replacement was XFrames, which attempts to solve the problem of addressing a populated frameset through composite URIs.
The later HTML5 standard, which took a different approach to succession from HTML 4, also removes framesets. The
iframe element, however, remains, with a number of "sandboxing" options intended for sharing content between sites.
By allowing content to be loaded and navigated independently, frames offered several advantages over the plain HTML in use when they were first developed:
The practice of framing HTML content led to numerous criticisms, most centering on usability and accessibility concerns. These include:
As web technology developed, many of the purposes for which frames were used became possible in ways that avoided the problems identified with frames.
overflowproperty) or held on screen while other content is scrolled (using
Not all of problems identified with framesets are eliminated by using these alternative approaches; for instance issues with Back/Forward navigation, bookmarking, and indexing remain on many sites which make heavy use of DHTML / AJAX navigation.