Identifier

An identifier is a sequence of characters in the code that identifies a variable, function, or property.

In JavaScript, identifiers are case-sensitive and can contain Unicode letters, $, _, and digits (0-9), but may not start with a digit.

An identifier differs from a string in that a string is data, while an identifier is part of the code. In JavaScript, there is no way to convert identifiers to strings, but sometimes it is possible to parse strings into identifiers.