3 ms·
Worth noting that `undefined` is a variable, and not a keyword. undefined = 1; >>> 1 null = 1; >>> ReferenceError: invalid assignment left-hand sid
by underwater 15y ago
Worth noting that `undefined` is a variable, and not a keyword.
undefined = 1;
>>> 1
null = 1;
>>> ReferenceError: invalid assignment left-hand side
It looks like Chrome and Firefox no longer let you assign to window.undefined any, but I'm not sure is IE has the same restrictions. The correct way to check for undefined is via `typeof`.