Identifier

{{GlossarySidebar}} 

An identifier is a sequence of characters in the code that identifies a {{glossary("variable")}} , {{glossary("function")}} , or {{glossary("property")}} . In most languages, identifiers are case-sensitive and not quoted.

In {{glossary("JavaScript")}} , identifiers can contain {{glossary("Unicode")}}  letters, $, _, and digits (0-9), but may not start with a digit. An identifier differs from a string in that a {{glossary("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.

In {{glossary("CSS")}} , there are two identifier data types: {{cssxref("custom-ident")}}  and {{cssxref("dashed-ident")}} . The CSS {{cssxref("ident")}}  can contain almost any character, but non-letter/digit ASCII characters such as ", \, and * must be escaped, it must not start with a digit, and emojis are valid as identifiers that do not require escaping.

See also

• Related glossary terms:
  • {{glossary("Scope")}} 
  • {{glossary("string")}} 
  • {{glossary("Unicode")}} 
• Identifier on Wikipedia