Negative lookahead Regular Expression

Question

I want to match all strings ending in \".htm\" unless it ends in \"foo.htm\". I\'m generally decent with regular expressions, but negative lookaheads have me stumped. Why

Answer 1

You could emulate the negative lookbehind with something like /(.|..|.*[^f]..|.*f[^o].|.*fo[^o])\.htm$/, but a programmatic approach would be better.