# Tag Features

Features common to many of the HTML tags

TAGS: Cyber Tech, HTML, Standards, TECH

!-- (HTML comment) | !DOCTYPE | a | abbr | acronym | address | applet | area | b | base | basefont | bdo | big | blockquote | body | br | button | caption | center | cite | code | col | colgroup | dd | del | dfn | dir | div | dl | dt | em | fieldset | font | form | frame | frameset | h1 | h2 | h3 | h4 | h5 | h6 | head | hr | html | i | iframe | img | input | ins | isindex | kbd | label | legend | li | link | map | menu | meta | noframes | noscript | object | ol | optgroup | option | p | param | pre | q | s | samp | script | select | small | span | strike | strong | style | sub | sup | table | tbody | td | textarea | tfoot | th | thead | title | tr | tt | u | ul | var

This page discusses features common to many of the HTML tags. Also included is the syntax I used in listing the HTML tags.

## Tag Syntax

Here are general syntax rules that apply to all the tags:

• Most of the tags have the same syntax. Notable exceptions the above syntax includes the structural SGML tags. Here are the two basic syntaxes:
<TagName> ContentEnclosedByTags  </TagName>
<TagName />

• Each tag may have one or more attributes whose values may be set. EG:
<h1 align="center">Welcome</h1>
• Each tag may have one or more intrinsic events that can set for detection. EG:
<b onmouseover="DoThis()">Show Me</b>
• Each attribute or intrinsic event may have one or more properties whose values may be set. EG:
<p style="font-size:5; color:#990000;">
• There are several simple rules to make an HTML document a well formed XHTML document. These should be followed as much as possible in case the document is ever translated to an XHTML document.

## Common Attributes

• ACCESSKEY. Indicates a letter that can be used as a keyboard shortcut to put focus on the tag. This is typically ALT+AccessKey for PCs and CTRL+AccessKey for Macs. For Windows, the presence of an HTML accesskey takes precedence of application access keys. EG: If you put in an HTML accesskey of "h", then it is accessed by pressing "ALT+h" and the application's help menu is accessed by pressing "ALT" then "h". Applies to the following elements: a, area, button, input, label, legend, and textarea.
• CLASS. A list of classes affecting the element. Applies to all elements except for: base, basefont, head, html, meta, param, script, style, and title.
• DIR. The direction the text is read, i.e. either ltr or rtl.
• DISABLED. Indicates a disabled control. Applies to the following tags: button, input, optgroup, option, select, and textarea.
• ID. An identifier for the element, unique on the page. Applies to all elements except for: base, head, html, meta, script, style, and title.
• NAME. Usually identifies the item in question. The ID attribute is usually much clearer.
• LANG. Identifies the ISO language used. See also my section on Language. Applies to all elements except for: applet, base, basefont, br, frame, frameset, iframe, param, and script.
• STYLE. Inline CSS application. Applies to all elements except for: base, basefont, head, html, meta, param, script, style, and title.
• TABINDEX. A number between 0 and 32767 which indicates the position of the current item in the tabbing order. This attribute applies to the following tags: a, area, button, input, object, select, and textarea.
• TARGET. The name of the frame where a document will be opened. This is is used by <a>, <link>, <area>, and <form>. The following frame names are reserved and have special meaning:
• _blank. The browser should load the designated document in a new, unnamed window.
• _self. The default. The browser should load the document in the same frame as the element that refers to this target.
• _parent. The browser should load the document into the immediate FRAMESET parent of the current frame. This value is equivalent to _self if the current frame has no parent.
• _top. The browser should load the document into the full, original window (thus canceling all other frames). This value is equivalent to _self if the current frame has no parent.
• TITLE. Information about the element. This not to be confused with the <title> tag which is for the whole document. The value of TITLE is commonly rendered as a "tool tip" (a message that pops up when the cursor is held over an object) or as audio (for audio browsers).  Applies to all elements except for: base, basefont, head, html, meta, param, script, and title.
• TYPE. This has different meanings depending on the tag!
• VALUE. This has different meanings depending on the tag!

## Common Intrinsic Events

• onclick
• ondblclick
• onkeydown. Pressed and held.
• onkeyup. Pressed, held, and released.
• onmousedown. Pressed and held.
• onmouseup. Pressed, held, and released.
• onmouseover. Move cursor on to an object.
• onmousemove. Move cursor.
• onmouseout. Move cursor off an object.

## Tag Stats

Tags Start
/End
Empty Depr.
/FP
DTD Type
91 4 OO

13 / FF
15 / OO

13 EE 10 XX

8 / FP

11 LD
3 FD
13 SL
37 BL
43 TL

Note that there are 93 of the three types of tags because the <isindex> tag is both a SL and BL tag, and the <script> tag is both a SL and TL tag.

## Tag Listings Syntax

Here is the syntax I used in listing the HTML tags:

[StartTag/EndTag][EE ][XX][FP]. [Description. ][TagGroup.]

Legend:

• OO. Optional.
• FF. Forbidden.
• EE. Empty.
• XX. Deprecated.
• LD. Loose DTD,
• FD. Frameset DTD.
• FP. Not directly supported by Microsoft FrontPage.
• SL. Structural Level.
• BL. Block Level
• TL. Text Level.

A DTD (Document Type Definition) is a document that defines an SGML compliant markup language. See also the SGML <!doctype> tag. Here are the three DTDs that are used in defining HTML 4.01:

• Strict DTD. Formal HTML 4.01 without any deprecated tags.
• Loose DTD, aka Transitional DTD. This is Strict DTD plus some of the tags that are deprecated.
• Frameset DTD. This is Loose DTD but with the <body> tag replaced by the <frameset> tag.

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