The id attribute assigns a unique name to an element. Similar to the name attribute of the <a> element, but it allows any element in the document body to be the destination of a link.
footnotes:Style sheet rules can be assigned to specific id values (unlike the obsolete name attribute).
If your Web browser supports style sheets, the following should produce a centered and italicized paragraph.
poem identifier:Higgledy‐piggledy
			Nic’laus Copernicus
			Looked at the Universe
			Spoke to the throng
			Give up your Ptolemy
			Rise up and follow me,
			Heliocentrically
			Ptolemy’s wrong
The class attribute assigns class names to an element. Classes are used as style sheet selectors.
If your Web browser supports style sheets, the following should produce a paragraph with an underlined, blue phrase.
fake and link classes:<span> with two classes, fake and link:Your Web browser identified itself as Wget/1.11.4 when it requested this page.