HTML - Attribute

About

An attribute in HTML is an XML attribute of an HTML element

Property

Name

Attribute names are case-insensitive.

Special

Classes and IDs are attributes used in the selection of element. Class and ID names cannot begin with numerals; they must begin with alphabetic characters.

Order

Order does not matter but some attributes are more searched (ie have more functionality) while reading HTML.

The code guide gives the following order that reflects this idea

• class
• id, name
• data-*
• src, for, type, href, value
• title, alt
• role, aria-*

Without any value

See What are Boolean Attribute in HTML ?

How to access HTML Attribute via Javascript

See Attribute manipulation with DOM

How to track the modification of values?

See How to use MutationObserver to track mutation on the DOM ?

Note on Body attributes modifications: If a document has two body elements, it's possible that the browser will overwrite the attributes of the first body element with the attributes of the second.