Can you use reserved words in JavaScript?

In JavaScript, you cannot use these reserved words as variable names, label names, or function names. Removed Reserved Words: The following reserved words have been removed from ECMAScript 5 and 6. Other Reserved Words: JavaScript can be used as the programming language in many applications. 1.

What is a reserved identifier?

In any programming language, a reserved word or a reserved identifier is a word that cannot be used as an identifier, such as the name of a variable, function, or label. Thus, it is reserved and cannot be used for defining any of these. This is a syntactic definition, and a reserved word may have no meaning.

Do all reserved words cause problems in all browsers?

Not all of these reserved words will cause problems in all browsers, but it’s best to steer clear of these names when naming variables.

How do I know if an array is a reserved word?

An array should do, if the value exists in the array then it's a reserved word. return !!~reservedWords.indexOf (str); Why not just return reservedWords.indexOf (str) > -1;?