JavaScript Reserved Words

JavaScript has a number of reserved words that you cannot use as identifiers. Reserved words have a specific meaning to the JavaScript language, as they are part of the language syntax. Using a reserved word causes a compilation error when loading your script.

JavaScript also has a list of future reserved words. These words are not currently part of the JavaScript language, although they are reserved for future use. For more information about future reserved keywords in JavaScript, see JavaScript Future Reserved Words.

When choosing identifiers it is also important to avoid any words that are already the names of intrinsic JavaScript objects or functions, such as String or parseInt.

Reserved Keywords

break default function return var
case delete if switch void
catch do in this while
const else instanceof throw with
continue finally let try
debugger for new typeof