Check whether a name is a valid JavaScript identifier and explain each problem — digits, symbols, spaces or reserved keywords. JS Variable Name Validator is a free online tool from the ToolsRift JavaScript Tools collection. It runs entirely in your browser — nothing to install, no signup, and your data never leaves your device.
Type or paste a variable name, then click Validate. You get a valid / invalid verdict plus a list of exactly what is wrong.
It must start with a letter, $ or _, contain only letters, digits, $ or _, be non-empty, and must not be a reserved JavaScript keyword.
Keywords like class, return, let, function, new and future-reserved words such as enum and implements cannot be used as identifiers.
JavaScript permits some Unicode identifiers, but this validator checks the standard ASCII rules and will flag non-ASCII characters as invalid for portability.