HTML Attributes

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.

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 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.