Common XHTML Tags

The following are some facts about HTML and XHTML tags:

Web pages are just plain text. You can view or edit the source code using any text editor.
"Tags" provide web browsers with instructions about the web page, such as where to display images, and how the document is structured.
Tags are always enclosed in angle brackets: < >.
Tags are comprised of elements and attributes. An element is an object on a page (such as a heading, paragraph, or image), and attributes are qualities that describe that element (such as width and height).
Tags usually travel in pairs. An opening tag begins a section of page content, and a closing tag ends it. For example, to markup a section of text as a paragraph, you would open the paragraph with an opening paragraph tag  and close it with a closing paragraph tag  (closing tags always proceed the element with a /).
A few tags are called non-container tags, because they don't contain any content - they stand alone. Examples are images and line breaks. XHTML requires that all open tags must be closed, even if they're not container tags. Therefore, non-container tags end in />. For example, the tag for a line break is  .
Tags in HTML are not case sensitive, but in XHTML all tags must be in lower case. Even when coding in HTML, you should get in the habit of writing tags in lower case.
White space is ignored by web browsers. So, if you hit the space bar multiple times within a document, only one of those spaces will actually be displayed by the browser.
Tags can be nested. For example,  this text is italicized and bold . Note that the order of nested tags is important: The container tags surrounding any content should be symmetrical.

Understanding the following tables:

Common HTML tags are presented below, organized into four tables based on their purpose. The first table includes tags that control the overall structure of the web page. The second and third tables include tags that mark up the majority of web page content. Container tags (those that contain content) are presented in the second table, and non-container tags (those that stand alone) are presented in the third table. The final table contains tags that are used in markup of HTML tables, which are covered in Module 5 of this unit.

Document Structure

Opening Tag	Closing Tag	Description
<html>	</html>	Identifies the document as HTML
<head>	</head>	Identifies the header section of your document, which is used to provide information about the document for use primarily by search engines and browsers.
<title>	</title>	The title of document. This element must be nested within the head elements.
<body>	</body>	Contains all the visible content of a web page.

Content (Container) Tags

Opening Tag	Closing Tag	Description
<h1> to <h6>	</h1>to</h6>	Headings. H1 is the main heading, H2 is secondary, etc.
<p>	</p>	New paragraph
<div> or <span>	</div> or </span>	Serve as a containers for content
<em>	</em>	Gives the contained text emphasis (usually as italics).
<strong>	</strong>	Makes the contained text bold.
<a href = "document location">	</a>	Link to another document
<a name = "label">	</a>	Link to another section of the same page
<ol>	</ol>	Makes ordered lists
<ul>	</ul>	Makes unordered (or bulleted) lists
<li>	</li>	Marks items in either the ordered or unordered list.

Empty (Non-Container) Tags

Tag	Description
<br />	Causes a line break. It may be repeated for multiple line breaks.
<hr />	Horizontal rule. It creates a line to separate content.
<img src ="image location" />	Inserts an image into a web page
<p />	The paragraph tag used in this manner serves as a double line break. It does not contain text. Unlike the <br /> tag it cannot be used multiple times to generate more white space.

Tables

Opening Tag	Closing Tag		Description
<table>	</table>		Adds table
		border="number"	Border for rows & columns
		cellpadding	Thickness of cell wall
		cellspacing	Spacing between border and cell contents
		bgcolor	Background color of cells
<tr>	</tr>		Table row (start & end)
		align="left, center, right"	Aligns text in row horizontally
		align="top, middle, bottom"	Aligns text in row vertically
<th scope="row" > <th scope="col" >	</th>		When creating a table to display data, use this tag to differentiate the first row or column of cells as heading cells for all the other cells in the same column or row. Content will automatically be bold and center aligned. The scope attribute defines which data cells pertain to the heading.
<td>	</td>		Defines data cell
		colspan="number"	Spans cells across column
		rowspan="number"	Spans cells across row
		align	Alignment in cell

Copyright © 2006 by University of Washington. Permission is granted to copy these materials for educational, noncommercial purposes provided the source is acknowledged. This product was funded by the National Institute on Disability and Rehabilitation Research of the U.S. Department of Education (grant #H133D010306). However, the contents do not necessarily represent the policy of the Department of Education, and you should not assume their endorsement.

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