DevGuru HTML: Non-standard Tags

Other HTML Tags
These tags are not recognized by the W3C HTML version 4.01 standard. However, it is quite possible that you may find some of these tags to be of considerable value.

<audioscope>
The audioscope tag is used with WebTV to display the audioscope, which is a graphical display of sound waves.

<bgsound>
The bgsound tag is placed in the head element and is used to add sound to a web site.

<blackface> ... </blackface>
The blackface tag is used with WebTV to display text in a double weight bold font face.

<blink> ... </blink>
The blink tag causes the selected text to blink.

<bq>
The bq tag is used with WebTV to display a block quote.

<comment> ... </comment>
The comment tag allows the addition of comments to HTML documents created for display on Internet Explorer and WebTV.

<embed>
The embed tag is used with Netscape and allows the automatic display of a plug-in application.

<fn> ... </fn>
The fn tag is used with WebTV to display footnotes.

<ilayer> ... </ilayer>
The ilayer tag creates an inline layer.

<keygen>
The keygen tag is used with Netscape for encryption.

<layer> ... </layer>
The layer tag is used with Netscape to create multiple layers of text and images which lay in order, one on top of the other. Usually the lower layers are partially visible through the upper layers.

<limittext>
The limittext tag is deprecated by WebTV. It is used to set the width of the text display.

<listing> ... </listing>
The listing tag is deprecated by W3C HTML version 3.2. It displays text just like the pre tag.

<marquee> ... </marquee>
Code:
<marquee width="85%">
The marquee tag is used with Internet Explorer and WebTV to display a scrolling text.
</marquee>

Output:
The marquee tag is used with Internet Explorer and WebTV to display a scrolling text.

<multicol> ... </multicol>
The multicol tag is used with Netscape to format and display a multiple column flow of text and images.

 ... 
The nobr tag is widely implemented. It prevents any line breaks from occurring in a flow of text.

<noembed> ... </noembed>
The noembed tag is used with Netscape to display an alternative text for browsers that do not recognize the embed tag.

<nosmartquotes> ... </nosmartquotes>
The nosmartquotes tag is used with WebTV to prevent regular single '...' and double "..." quotes from automatically being replaced with smart single ‘...’ and smart double “...” quotes.

<plaintext>
The plaintext tag designates that all HTML tags are to be ignored and that the text is to be displayed as it is written.

<rt>
The rt tag is used to denote the annotation or pronunciation text used by the ruby tag.

<ruby> ... </ruby>
The ruby tag is used with Internet Explorer to create an annotation or pronunciation guide for a base text. The guide (called a ruby text) appears either inline or above the base text.

Code:
The <ruby>Sotano de las Golondrinas

<rt>Pit of the Swallows

</ruby> is in Mexico.

Output:
The Sotano de las Golondrinas Pit of the Swallows is in Mexico.

<server> ... </server>
The server tag is used with Netscape to insert server-side JavaScript into an HTML document.

<shadow>
The shadow tag is used with WebTV to add a shadow to text.

<sidebar>
The sidebar tag is used with WebTV to create a sidebar window that displays control elements.

<spacer>
The spacer tag is used with Netscape to add white space between words.


The wbr tag is used inside a nobr element to add a line break.

<xml> ... </xml>
The xml tag is used with Internet Explorer to delimit an XML data island inside an HTML page.

<xmp> ... </xmp>
The xmp tag is deprecated by W3C HTML version 3.2. It is equivalent to using:
<pre width="80"> ... </pre>