HTML Attributes

Attributes are another important part of HTML markup. An attribute is used to define the characteristics of an element and is placed inside the element's opening tag. All attributes are made up of two parts: a name and a value:

• The name is the property you want to set. For example, the element in the example carries an attribute whose name is face, which you can use to indicate which typeface you want the text to appear in.
• The value is what you want the value of the property to be. The first example was supposed to use the Arial typeface, so the value of the face attribute is Arial.

The value of the attribute should be put in double quotation marks, and is separated from the name by the equals sign. You can see that a color for the text has been specified as well as the typeface in this element:

Many HTML tags have a unique set of their own attributes. These will be discussed as each tag is introduced throughout the tutorial. Right now we want to focus on a set of generic attributes that can be used with just about every HTML Tag in existence.

Core Attributes:

The four core attributes that can be used on the majority of HTML elements (although not all) are:

• id
• title
• class
• style

The id Attribute:

The id attribute can be used to uniquely identify any element within a page ( or style sheet ). There are two primary reasons that you might want to use an id attribute on an element:

• If an element carries an id attribute as a unique identifier it is possible to identify just that element and its content.
• If you have two elements of the same name within a Web page (or style sheet), you can use the id attribute to distinguish between elements that have the same name.

We will discuss style sheet in separate tutorial. For now, the id attribute could be used to distinguish between two paragraph elements, like so:

This para explains what is HTML This para explains what is Casecading Style Sheet

Note that there are some special rules for the value of the id attribute, it must:

• Begin with a letter (A.Z or a.z) and can then be followed by any number of letters, digits (0.9), hyphens, underscores, colons, and periods.
• Remain unique within that document; no two attributes may have the same value within that HTML document.

The title Attribute:

The title attribute gives a suggested title for the element. They syntax for the title attribute is similar as explained for id attribute:

The behavior of this attribute will depend upon the element that carries it, although it is often displayed as a tooltip or while the element is loading.

For example:

Titled Heading Tag Example

Above code will generate following result:

Titled Heading Tag Example

Now try to bring your cursor over "Titled Heading Tag Example" and see the result.

The class Attribute:

The class attribute is used to associate an element with a style sheet, and specifies the class of element. You learn more about the use of the class attribute when you will learn Casecading Style Sheet (CSS). So for now you can avoid it.

The value of the attribute may also be a space-separated list of class names. For example:

class="className1 className2 className3"

The style Attribute:

The style attribute allows you to specify CSS rules within the element. For example:

Some text...

Internationalization Attributes:

There are three internationalization attributes, which are available to most (although not all) XHTML elements.

• dir
• lang
• xml:lang

The dir Attribute:

The dir attribute allows you to indicate to the browser the direction in which the text should flow.The dir attribute can take one of two values, as you can see in the table that follows:

Value	Meaning
ltr	Left to right (the default value)
rtl	Right to left (for languages such as Hebrew or Arabic that are read right to left)

Example:

This is how IE 5 renders right-to-left directed text.

When dir attribute is used within the tag, it determines how text will be presented within the entire document. When used within another tag, it controls the text's direction for just the content of that tag.

The lang Attribute:

The lang attribute allows you to indicate the main language used in a document, but this attribute was kept in HTML only for backwards compatibility with earlier versions of HTML. This attribute has been replaced by the xml:lang attribute in new XHTML documents.

When included within the tag, the lang attribute specifies the language you've generally used within the document. When used within other tags, the lang attribute specifies the language you used within that tag's content. Ideally, the browser will use lang to better render the text for the user.

The values of the lang attribute are ISO-639 standard two-character language codes.Check HTML Language Codes: ISO 639 for a complete list of language codes.

Example:

This page is using English Language

The xml:lang Attribute:

The xml:lang attribute is the XHTML replacement for the lang attribute. The value of the xml:langattribute should be an ISO-639 country code as mentioned in previous section.

Generic Attributes:

Here's a table of some other attributes that are readily usable with many of HTML's tags.

Attribute	Options	Function
align	right, left, center	Horizontally aligns tags
valign	top, middle, bottom	Vertically aligns tags within an HTML element.
bgcolor	numeric, hexidecimal, RGB values	Places a background color behind an element
background	URL	Places an background image behind an element
id	User Defined	Names an element for use with Cascading Style Sheets.
class	User Defined	Classifies an element for use with Cascading Style Sheets.
width	Numeric Value	Specifies the width of tables, images, or table cells.
height	Numeric Value	Specifies the height of tables, images, or table cells.
title	User Defined	"Pop-up" title for your elements.

We will see related examples as we will proceed to study other HTML tags.

For a complete list of HTML Tags and related attributes please check reference to HTML Tags List.

More about → HTML Attributes

HTML Meta Tags

HTML lets you specify metadata - information about a document rather than document content -in a variety of ways. The META element can be used to include name/value pairs describing properties of the HTML document, such as author, Expiry Date, a list of key words, author etc.

The tag is an empty element and so does not have a closing tag, rather, tags carry information within attributes, so you need a forward slash character at the end of the element.

Metadata provided by using meta tag is a very important part of the web. It can assist search engines in finding the best match when a user performs a search. Search engines will often look at any metadata attached to a page - especially keywords - and rank it higher than another page with less relevant metadata, or with no metadata at all.

Adding Meta Tags to Your Documents:

You can add metadata to your web pages by placing tags between the and tags. The can include the following attributes:

Attribute	Description
Name	Name for the property. Can be anything. Examples include, keywords, description, author, revised, generator etc.
content	Specifies the property's value.
scheme	Specifies a scheme to use to interpret the property's value (as declared in the content attribute).
http-equiv	Used for http response message headers. For example http-equiv can be used to refresh the page or to set a cookie. Values include content-type, expires, refresh and set-cookie.

NOTE: Core attributes for all the elements are discussed in next chapter.

Meta Tag Examples:

Let's see few important usage of Meta Tags.

Specifying Keywords:

We specify keywords which will be used by the search engine to search a web page. So using following tag you can specify important keywords related to your page.

Document Description:

This is again important information and many search engine use this information as well while searching a web page. So you should give an appropriate description of the page.

Document Revision date:

This information tells about last time the document was updated.

Document Refreshing:

You can specify a duration after which your web page will keep refreshing. If you want your page keep refreshing after every 10 seconds then use the following syntax.

Page Redirection:

You can specify a page redirection using Meta Tag. Following is an example of redirecting current page to another page. You can specify a duration after which page will be redirected.

If you don't provide a duration then page will be redirected immediately.

Setting Cookies:

You can use Meta Tag to store cookies on client side later information can be used by then Web Server to track a site visitor.

If you do not include the expiration date and time, the cookie is considered a session cookie and will be deleted when the user exits the browser.

Check PHP and Cookies tutorial for a complete detail on Cookies.

Setting Author Name:

You can set an author name in a web page using Meta Tag. See an example below:

If you do not include the expiration date and time, the cookie is considered a session cookie and will be deleted when the user exits the browser.

More about → HTML Meta Tags