Why does the JavaScript RegExp /^\w+$/ match undefined?
firefox, javascript, regex
Solution
When `undefined` is cast to a string (which the regex does), it produces the string `"undefined"`, which is then matched.
Problem
Why does the the RegExp `/^\w+$/` match `undefined`? Example code: ``` alert(/^\w+$/.test(undefined)); ``` This will display true in Firefox 3 (only browser I tested it on).