XHTML Structure

XHTML relies on several elements to provide structure to a document (as opposed to structuring the text within) as well as to provide information that is used by the browser or search engines.

`<bdo>`…`</bdo>`

Usage	The bidirectional algorithm element used to selectively turn off the default text direction.
Start/End Tag	Required/Required.
Attributes	`core`. `lang="language"` The language of the document. `dir="direction"` The text direction (`ltr`, `rtl`). Mandatory attribute.
Empty	No.

`<body>`…`</body>`

Usage	Contains the document's content.
Start/End Tag	Optional/Optional.
Attributes	`core`, `i18n`, `events`. `onload="eventcode"` Intrinsic event triggered when the document loads. `onunload="eventcode"` Intrinsic event triggered when document unloads.
Empty	No.
Notes	There can be only one `<body>`, and it must follow the `<head>`. The `<body>` element can be replaced by a `<frameset>` element.

Comments ``

Usage	Used to insert notes or scripts that are not displayed by the browser.
Start/End Tag	Required/Required.
Attributes	None.
Empty	Yes.
Notes	Comments are not restricted to one line and can be any length. The end tag is not required to be on the same line as the start tag.

`<div>`…`</div>`

Usage

The division element is used to add structure to a block of text.

Start/End Tag

Required/Required.

Attributes

core, i18n, events.

By the Way

You may run across HTML web pages that use the <div> element with an attribute named align. This attribute was removed in XHTML, with the new approach to alignment involving the text-align CSS style property. This style property is covered later in this appendix.

Empty

No.

Notes

Cannot be used within a p element.

`<!doctype...>`

Usage	Version information appears on the first line of an HTML document and is an SGML declaration rather than an element.

`<h1>`…`</h1>` Through `<h6>`…`</h6>`

Usage	The six headings (`h1` is uppermost, or most important) are used in the `body` to structure information in a hierarchical fashion.
Start/End Tag	Required/Required.
Attributes	`core`, `i18n`, `events`.
Empty	No.
Notes	Visual browsers will display the size of the headings in relation to their importance, `<h1>` being the largest and `<h6>` being the smallest.

`<head>`…`</head>`

Usage	This is the document header and it contains other elements that provide information to users and search engines.
Start/End Tag	Optional/Optional.
Attributes	`i18n`. `profile="url"` URL specifying the location of `meta` data.
Empty	No.
Notes	There can be only one `<head>` per document. It must follow the opening `<html>` tag and precede the `<body>`.

`<hr />`

Usage	Horizontal rules are used to separate sections of a web page.
Start/End Tag	Required/Illegal.
Attributes	`core`, `events`, `i18n`.
Empty	Yes.

`<html>`…`</html>`

Usage	The `html` element contains the entire document.
Start/End Tag	Optional/Optional.
Attributes	`i18n`.
Empty	No.
Notes	The version information is duplicated in the `<!doctype...>` declaration and is therefore not essential.

`<meta />`

Usage	Provides information about the document.
Start/End Tag	Required/Illegal.
Attributes	`i18n`. `http-equiv="servercmd"` HTTP response header name. `name="name"` Name of the `meta` information. `content="value"` Content of the `meta` information. `scheme="scheme"` Assigns a scheme to interpret the `meta` data.
Empty	Yes.

`<span>`…`</span>`

Usage	Organizes the document by defining a span of text.
Start/End Tag	Required/Required.
Attributes	`core`, `i18n`, `events`.
Empty	No.

`<title>`…`</title>`

Usage	The name you give your web page. The `<title>` tag is placed in the `<head>` tag and is displayed in the browser window title bar.
Start/End Tag	Required/Required.
Attributes	`i18n`.
Empty	No.
Notes	Only one title allowed per document.

<bdo>…</bdo>

<body>…</body>

Comments

<div>…</div>

By the Way

<!doctype...>

<h1>…</h1> Through <h6>…</h6>

<head>…</head>

<hr />

<html>…</html>

<meta />

<span>…</span>

<title>…</title>