HTML Part 4

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 <font> 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 <font> element:
<font face="arial" color="#CC0000"> 
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:

<p id="html">This para explains what is HTML</p>
<p id="css">This para explains what is Casecading Style Sheet</p>

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: 

<h4 title="Hello HTML!">Titled Heading Tag Example</h4>  

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: 

<p style="font-family:arial; color:#FF0000;">Some text...</p> 

Internationalization Attributes: 

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

•  dir  
•  lang  
•  xml:lang