-HTML Attributes

Attributes provide additional information to an HTML element.
HTML Tag AttributesHTML tags can have attributes. Attributes provide additional information to an HTML element.
Attributes always come in name/value pairs like this: name="value".
Attributes are always specified in the start tag of an HTML element.
Attributes Example 1:

defines the start of a heading.

has additional information about the alignment.
Try it yourself: Center aligned heading
Attributes Example 2:
defines the body of an HTML document.
has additional information about the background color.
Try it yourself: Background color
Attributes Example 3:
defines an HTML table. (You will learn more about HTML tables later)
has additional information about the border around the table.
Use Lowercase Attributes
Attributes and attribute values are case-insensitive. However, the World Wide Web Consortium (W3C) recommends lowercase attributes/attribute values in their HTML 4 recommendation, and XHTML demands lowercase attributes/attribute values.
Always Quote Attribute Values
Attribute values should always be enclosed in quotes. Double style quotes are the most common, but single style quotes are also allowed.
In some rare situations, like when the attribute value itself contains quotes, it is necessary to use single quotes:
name='John "ShotGun" Nelson'