Attributes are “name-value” pair, changes the behavior of HTML Elements. Attributes
always used with HTML element start tag or opening tag.

HTML Attributes are of 4 types:

  1. Required Attributes
  2. Optional Attributes
  3. Standard Attributes
  4. Event Attributes

1) Required Attributes: HTML Elements need attributes to work properly

Example:
<input type="submit" value="Post" />

2) Optional Attributes: changes the behaviour of HTML Elements.

Example:
<div style="border:1px solid black;">Hello world</div>

3) Standard Attributes: Attributes that are common to all HTML Elements also called as
Global Attributes

Example:
class, id, accesskey, data, title etc.

4) Event Attributes: Attributes which invokes javascript function, when user interact with specific HTML element.

Example:
onclick, onblur, onfocus, onload, onkeyup etc.

HTML 5 does not require double qoutes arround its value.

Example:

<html>
<head>
</head>
<body>

<div align="right">
Hello World....
</div>

<a href="" title="Click to open me">Hello</a>

</body>
</html>