Frames

Frames are a way to show more than one web page simultaneously. Its use is being discouraged. In XHTML 1.1 there is no support for frames. We will discuss frames from the sake of completeness and then see how we can replace them.

The starting point for a document with frames is an HTML page that has the body element replaced with frameset. Here is an example:

<html>
<head>
...
</head>

<frameset rows = "50, *">
  <frame name = "navbar" src = "./nav.html">
  <frame name = "main" src = "./synopsis.html">

  <noframes>
    <body>
      <p>
        This page uses frames. Here is the 
	<a href = "./noframes.html"> no frames </a> version.
      </p>
    </body>
  </noframes>
</frameset>
</html>

Here is the html page for the navigation bar:

<html>
<head>
...
</head>

<body>
  <h2> Magnum Opus </h2>
  [<a href = "./chap1.html" target = "main"> Chapter 1 </a>]
  [<a href = "./chap2.html" target = "main"> Chapter 2 </a>]
  [<a href = "./chap3.html" target = "main"> Chapter 3 </a>]
  [<a href = "./chap4.html" target = "main"> Chapter 4 </a>]
</body>
<html>

Here is the html page for the synopsis:

<html>
<head>
...
</head>

<body>
<h2> Synopsis  </h2>
<p>
  It was a dark and stormy night!
</p>
</body>
<html>

Frames can be nested. Use the element frameset instead of the element frame to achieve the desired level of nesting. The attribute target can have several different types of values. Usually it has the name of the frame where the page is to be displayed.

_blank : loads the page into a new browser window
_self : loads the page into the frame in which the anchor element appears
_top : loads the page into the full browser window (i.e. removes the frameset)

Here is an example of a regular frame.

Why no Frames

Frames break the unified model of the Web. The user's view is determined by a sequence of navigation actions rather than a single navigation action.
Bookmarks do not work because the bookmark does not represent the state of the frame since the URL no longer gives the complete specification of the information shown in the window.
Frames do not work well with small screens.
Many browsers cannot print framed pages appropriately.
Search engines do not know what composites of frames to include as navigation units in their index.
Use inline frames if you have to use frames.
Frames can be used as a shortcut for scrolling within a single page.
Frames are useful as comments to other pages.

Inline Frame

The iframe element allows authors to insert a frame within a block of text. The contents of the iframe element is displayed only by browsers that do not support frames or are configured not to display frames.

<iframe src = "./foo.html" width = "440" height = "500"
	   scrolling = "auto" frameborder = "1" >
[ Your browser does not support frames or 
  is currently configured not to display 
  frames. However, you may visit
  <a href = "./foo.html" > the related
  document </a> ]
</iframe>

Here is an example of an inline frame.