Forms
Named entities look like < for the less-than sign. Numeric entities use the character code, in decimal (<) or hex (<). Both display the same character.
The five that matter
These have to be escaped in HTML text and attributes: & (&), < (<), > (>), " (“) and ' (‘).
Try it
The HTML Entity Encoder/Decoder converts the five characters and decodes numeric entities. It leaves other named entities, such as the copyright sign’s name, unchanged. See the guide for examples.
Common misunderstanding
Pages served as UTF-8 do not need entities for accented letters or symbols; they can be typed directly. Entities are essential only for characters that HTML itself uses.