scriptular | A rubular.com clone for javascript regular expressions | Regex library

Variable re is a string literal, you need to create RegExp object then exec() can be used.

1.) The dot matches any character besides newline. It won't skip over newlines if the desired words would match in lines after the first one. In many regex flavors there is the dotall or single line s-flag available for making the dot also match newlines but unfortunately not in JS Regex.

Workarounds are to use a character class that contains any character. Such as [\s\S] any whitespace character \s together with any non whitespace \S or [\w\W] for any word character together with any non word character or even [^] for not nothing instead of the dot.

2.) Anchor the lookaheads to ^ start of string as it's not wanted to repeat the lookaheads at any position in the string. This will drastically improve performance.

3.) Use lazy matching for being satisfied with first match of each word.

You've passed it a string, not a regular expression, as the first argument. Make it a regular expression instead: