net.htmlparser.jericho

Class HTMLElements

java.lang.Object

HTMLElements

public final class HTMLElements
extends java.lang.Object

Contains static methods which group HTML element names by the characteristics of their associated elements.

An HTML element is a normal element with a name that matches one of the HTML element names (ignoring case). This type of element spans the logical HTML element as described in the HTML 4.01 specification section 3.2.1, which may be implicitly terminated if it specifies an optional end tag.

The term Non-HTML element refers to a normal element with a name that does not match one of the HTML element names. This type of element must be either a single tag element or explicitly terminated.

All of the sets returned by the methods in this class may be modified to customise the behaviour of the parser. Care must be taken however to ensure that the sets only contain tag names in lower case.

Below is a table summarising the default characteristics of each HTML element. See also the index of elements in the HTML 4.01 specification and draft HTML5 specification for the official tables containing similar information.

Name	vers	Box Type	Start Tag	End Tag	Nest	Depr.	Description / Specification
A		Inline		Required	NF		anchor
ABBR		Inline		Required			abbreviated form (e.g., WWW, HTTP, etc.)
ACRONYM		Inline		Required			acronym
ADDRESS		Block		Required	NF		information on author
APPLET		Inline		Required	NF	D	Java applet
AREA				Forbidden	NF		client-side image map area
article	5	Block		Required			self-contained syndicatable or reusable composition
aside	5	Block		Required			sidebar for tangentially related content
audio	5			Required			audio player
B		Inline		Required			bold text style
BASE				Forbidden	NF		document base URI
BASEFONT		Inline		Forbidden	NF	D	base font size
bdi	5	Inline		Required			text directionality isolation
BDO		Inline		Required			I18N BiDi over-ride
BIG		Inline		Required			large text style
BLOCKQUOTE		Block		Required			long quotation
BODY			Optional	Optional (details)	NF		document body
BR		Inline		Forbidden	NF		forced line break
BUTTON		Inline		Required	NF		push button
canvas	5			Required			scriptable bitmap canvas
CAPTION				Required	NF		table caption
CENTER		Block		Required		D	shorthand for DIV align=center
CITE		Inline		Required			citation
CODE		Inline		Required			computer code fragment
COL				Forbidden	NF		table column
COLGROUP				Optional (details)	NF		table column group
command	5			Forbidden	NF		menu command
datalist	5			Required	NF		container for options for combo box control
DD				Optional (details)			definition description
DEL		Inline		Required			deleted text
details	5	Block		Required			disclosure control for hiding details
DFN		Inline		Required			instance definition
DIR		Block		Required		D	directory list
DIV		Block		Required			generic language/style container
DL		Block		Required			definition list
DT				Optional (details)			definition term
EM		Inline		Required			emphasis
embed	5			Forbidden	NF		plugin
FIELDSET		Block		Required			form control group
figcaption	5			Required			caption for figure
figure	5			Required			figure with optional caption
FONT		Inline		Required		D	local change to font
footer	5	Block		Required			footer for a page or section
FORM		Block		Required	NF		interactive form
FRAME				Forbidden	NF		subwindow
FRAMESET				Required			window subdivision
H1		Block		Required			heading
H2		Block		Required			heading
H3		Block		Required			heading
H4		Block		Required			heading
H5		Block		Required			heading
H6		Block		Required			heading
HEAD			Optional	Optional (details)	NF		document head
header	5	Block		Required			introductory or navigational aids for a page or section
hgroup	5	Block		Required	NF		heading group
HR		Block		Forbidden	NF		horizontal rule
HTML			Optional	Optional (details)	NF		document root element
I		Inline		Required			italic text style
IFRAME		Inline		Required	NF		inline subwindow
IMG		Inline		Forbidden	NF		Embedded image
INPUT		Inline		Forbidden	NF		form control
INS		Inline		Required			inserted text
ISINDEX		Block		Forbidden	NF	D	single line prompt
KBD		Inline		Required			text to be entered by the user
keygen	5	Inline		Forbidden	NF		cryptographic key-pair generator form control
LABEL		Inline		Required	NF		form field label text
LEGEND				Required	NF		fieldset legend
LI				Optional (details)			list item
LINK				Forbidden	NF		a media-independent link
MAP		Inline		Required			client-side image map
mark	5	Inline		Required			highlight
MENU		Block		Required		D	menu list
META				Forbidden	NF		generic metainformation
meter	5	Inline		Required			gauge
nav	5	Block		Required			section with navigational links
NOFRAMES		Block		Required			alternate content container for non frame-based rendering
NOSCRIPT		Block		Required			alternate content container for non script-based rendering
OBJECT		Inline		Required			generic embedded object
OL		Block		Required			ordered list
OPTGROUP				Required	NF		option group
OPTION				Optional (details)	NF		selectable choice
output	5	Inline		Required			calculated output value
P		Block		Optional (details)	NF		paragraph
PARAM				Forbidden	NF		named property value
PRE		Block		Required			preformatted text
progress	5	Inline		Required			progress bar
Q		Inline		Required			short inline quotation
ruby	5	Inline		Required			ruby annotation(s)
rp	5	Inline		Required	NF		parenthesis for ruby annotation text
rt	5	Inline		Required	NF		ruby annotation text
S		Inline		Required		D	strike-through text style
SAMP		Inline		Required			sample program output, scripts, etc.
SCRIPT		Inline		Required	NF		script statements
section	5	Block		Required			generic document or application section
SELECT		Inline		Required	NF		option selector
SMALL		Inline		Required			small text style
source	5			Forbidden	NF		media source for video or audio
SPAN		Inline		Required			generic language/style container
STRIKE		Inline		Required		D	strike-through text
STRONG		Inline		Required			strong emphasis
STYLE				Required	NF		style info
SUB		Inline		Required			subscript
summary	5			Required			caption for details
SUP		Inline		Required			superscript
TABLE		Block		Required			table
TBODY			Optional	Optional (details)			table body
TD				Optional (details)			table data cell
TEXTAREA		Inline		Required	NF		multi-line text field
TFOOT				Optional (details)			table footer
TH				Optional (details)			table header cell
THEAD				Optional (details)			table header
time	5	Inline		Required			date and/or time
TITLE				Required	NF		document title
TR				Optional (details)			table row
TT		Inline		Required			teletype or monospaced text style
U		Inline		Required		D	underlined text style
UL		Block		Required			unordered list
VAR		Inline		Required			instance of a variable or program argument
video	5			Required			video player
wbr	5	Inline		Forbidden	NF		line breaking opportunity

See Also:

HTMLElementName, Element

Method Summary

Methods

Modifier and Type	Method and Description
static java.util.Set<java.lang.String>	getBlockLevelElementNames() Returns a set containing the names of all the block-level elements.
static java.util.Set<java.lang.String>	getDeprecatedElementNames() Returns a set containing the names of all deprecated elements in HTML 4.01.
static java.util.List<java.lang.String>	getElementNames() Returns a list containing all of the HTML element names.
static java.util.Set<java.lang.String>	getEndTagForbiddenElementNames() Returns a set containing the names of all of the HTML elements for which the end tag is forbidden.
static java.util.Set<java.lang.String>	getEndTagOptionalElementNames() Returns a set containing the names of all of the HTML elements for which the end tag is optional.
static java.util.Set<java.lang.String>	getEndTagRequiredElementNames() Returns a set containing the names of all of the HTML elements for which the end tag is required.
static java.util.Set<java.lang.String>	getInlineLevelElementNames() Returns a set containing the names of all the inline-level elements.
static java.util.Set<java.lang.String>	getNestingForbiddenElementNames() Returns a set containing the names of all of the HTML elements which should never contain elements of the same name, either as direct or indirect descendants.
static java.util.Set<java.lang.String>	getNonterminatingElementNames(java.lang.String endTagOptionalElementName) Returns the names of elements that do NOT implicitly terminate an HTML element with the specified name.
static java.util.Set<java.lang.String>	getStartTagOptionalElementNames() Returns a set containing the names of all of the HTML elements for which the start tag is optional.
static java.util.Set<java.lang.String>	getTerminatingEndTagNames(java.lang.String endTagOptionalElementName) Returns the names of end tags that implicitly terminate an HTML element with the specified name.
static java.util.Set<java.lang.String>	getTerminatingStartTagNames(java.lang.String endTagOptionalElementName) Returns the names of start tags that implicitly terminate an HTML element with the specified name.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getElementNames

public static final java.util.List<java.lang.String> getElementNames()

Returns a list containing all of the HTML element names.

The returned list is in alphabetical order.

Returns:

a list containing of all the HTML element names.

getBlockLevelElementNames

public static java.util.Set<java.lang.String> getBlockLevelElementNames()

Returns a set containing the names of all the block-level elements.

The element names contained in this set are:
ADDRESS, article, aside, BLOCKQUOTE, CENTER, details, DIR, DIV, DL, FIELDSET, footer, FORM, H1, H2, H3, H4, H5, H6, header, hgroup, HR, ISINDEX, MENU, nav, NOFRAMES, NOSCRIPT, OL, P, PRE, section, TABLE, UL

This set is defined in the HTML 4.01 Transitional DTD, but more detailed information can be found in the HTML 4.01 specification section 7.5.3 - Block-level and inline elements and the CSS2 specification section 9.2.1 - Block-level elements and block boxes.

The CSS2 display property can be used to override the normal box type of an element.

Returns:

a set containing the names of all the block-level elements.

See Also:

getInlineLevelElementNames()

getInlineLevelElementNames

public static java.util.Set<java.lang.String> getInlineLevelElementNames()

Returns a set containing the names of all the inline-level elements.

The element names contained in this set are:
A, ABBR, ACRONYM, APPLET, B, BASEFONT, bdi, BDO, BIG, BR, BUTTON, CITE, CODE, DEL, DFN, EM, FONT, I, IFRAME, IMG, INPUT, INS, KBD, keygen, LABEL, MAP, mark, meter, OBJECT, output, progress, Q, rp, rt, ruby, S, SAMP, SCRIPT, SELECT, SMALL, SPAN, STRIKE, STRONG, SUB, SUP, TEXTAREA, time, TT, U, VAR, wbr

This set is defined in the HTML 4.01 Transitional DTD, but more detailed information can be found in the HTML 4.01 specification section 7.5.3 - Block-level and inline elements and the CSS2 specification section 9.2.2 - Inline-level elements and inline boxes.

The CSS2 display property can be used to override the normal box type of an element.

The HTML Document Type Definitions forbid the presence of block-level elements inside inline-level elements, but it is tolerated by all popular browsers in various situations, even in XHTML documents. The most notorious example of this is the common inclusion of block-level elements inside FONT elements.

Returns:

a set containing the names of all the inline-level elements.

See Also:

getBlockLevelElementNames()

getDeprecatedElementNames

public static java.util.Set<java.lang.String> getDeprecatedElementNames()

Returns a set containing the names of all deprecated elements in HTML 4.01.

Returns:

a set containing the names of all deprecated elements in HTML 4.01.

getEndTagForbiddenElementNames

public static java.util.Set<java.lang.String> getEndTagForbiddenElementNames()

Returns a set containing the names of all of the HTML elements for which the end tag is forbidden.

See the element parsing rules for HTML elements with forbidden end tags for more information.

The index of elements in the HTML 4.01 specification includes the letter 'F' in the "End Tag" column for elements whose end tag is forbidden.

Returns:

a set containing the names of all of the HTML elements for which the end tag is forbidden.

See Also:

getEndTagOptionalElementNames(), getEndTagRequiredElementNames()

getEndTagOptionalElementNames

public static java.util.Set<java.lang.String> getEndTagOptionalElementNames()

Returns a set containing the names of all of the HTML elements for which the end tag is optional.

Elements with these names may be implicitly terminated by a subsequent terminating start tag or terminating end tag. A list of the these terminating tags, and the names of non-terminating elements that can be nested within the element, can be found in the documentation of each relevant element in the HTMLElementName class.

See the element parsing rules for HTML elements with optional end tags for more information.

The index of elements in the HTML 4.01 specification includes the letter 'O' in the "End Tag" column for elements whose end tag is optional.

Returns:

a set containing the names of all of the HTML elements for which the end tag is optional.

See Also:

getEndTagForbiddenElementNames(), getEndTagRequiredElementNames()

getEndTagRequiredElementNames

public static java.util.Set<java.lang.String> getEndTagRequiredElementNames()

Returns a set containing the names of all of the HTML elements for which the end tag is required.

See the element parsing rules for HTML elements with required end tags for more information.

The index of elements in the HTML 4.01 specification leaves the "End Tag" column blank for elements whose end tag is required.

Returns:

a set containing the names of all of the HTML elements for which the end tag is required.

See Also:

getEndTagForbiddenElementNames(), getEndTagOptionalElementNames()

getStartTagOptionalElementNames

public static java.util.Set<java.lang.String> getStartTagOptionalElementNames()

Returns a set containing the names of all of the HTML elements for which the start tag is optional.

Elements with optional start tags must be present in the document object model (DOM) in certain locations, either forming part of the structure of the HTML document as a whole (e.g. the HTML, HEAD, and BODY elements), or forming part of the structure of a TABLE element (e.g. the TBODY element). The location of an omitted start tag in the document's object model can be inferred from the surrounding elements.

This library does not use this property in any way when parsing documents, and does not construct a document object model from the source, so no implied element is created where an optional start tag is omitted.

When the start tag has been omitted in the document text, the corresponding end tag should also be omitted.

The index of elements in the HTML 4.01 specification includes the letter 'O' in the "Start Tag" column for elements whose start tag is optional.

Returns:

a set containing the names of all of the HTML elements for which the start tag is optional.

getTerminatingStartTagNames

public static java.util.Set<java.lang.String> getTerminatingStartTagNames(java.lang.String endTagOptionalElementName)

Returns the names of start tags that implicitly terminate an HTML element with the specified name.

This method is only relevant to HTML elements for which the end tag is optional. It returns null if
getEndTagOptionalElementNames().contains(endTagOptionalElementName.toLowerCase())==null.

Parameters:

endTagOptionalElementName - the name of an element for which the end tag is optional.

Returns:

the names of start tags that implicitly terminate an HTML element with the specified name, or null if the name does not identify an element for which the end tag is optional.

See Also:

getTerminatingEndTagNames(String endTagOptionalElementName), getNonterminatingElementNames(String endTagOptionalElementName)

getTerminatingEndTagNames

public static java.util.Set<java.lang.String> getTerminatingEndTagNames(java.lang.String endTagOptionalElementName)

Returns the names of end tags that implicitly terminate an HTML element with the specified name.

This method is only relevant to HTML elements for which the end tag is optional. It returns null if
getEndTagOptionalElementNames().contains(endTagOptionalElementName.toLowerCase())==null.

Note that removing the tag name matching the specified element has no effect on the behaviour of the parser, as it is always assumed that a start tag is terminated by an end tag with a matching name.

Parameters:

endTagOptionalElementName - the name of an element for which the end tag is optional.

Returns:

the names of end tags that implicitly terminate an HTML element with the specified name, or null if the name does not identify an element for which the end tag is optional.

See Also:

getTerminatingStartTagNames(String endTagOptionalElementName), getNonterminatingElementNames(String endTagOptionalElementName)

getNonterminatingElementNames

public static java.util.Set<java.lang.String> getNonterminatingElementNames(java.lang.String endTagOptionalElementName)

Returns the names of elements that do NOT implicitly terminate an HTML element with the specified name. Neither can any tag nested inside any of these elements implicitly terminate the specified element, even if it is listed as one of the terminating start tags or terminating end tags.

This method is only relevant to HTML elements for which the end tag is optional. It returns null if
getEndTagOptionalElementNames().contains(endTagOptionalElementName.toLowerCase())==null.

Parameters:

endTagOptionalElementName - the name of an element for which the end tag is optional.

Returns:

the names of elements that do NOT implicitly terminate an HTML element with the specified name, or null if the name does not identify an element for which the end tag is optional.

See Also:

getTerminatingStartTagNames(String endTagOptionalElementName), getTerminatingEndTagNames(String endTagOptionalElementName)

getNestingForbiddenElementNames

public static java.util.Set<java.lang.String> getNestingForbiddenElementNames()

Returns a set containing the names of all of the HTML elements which should never contain elements of the same name, either as direct or indirect descendants.

Returns:

a set containing the names of all of the HTML elements which should never contain elements of the same name.