This pops up every so often, and it sort of irritates me every time. Partially because it's overly simplistic, but, even more so, because, while it's cute and h

This pops up every so often, and it sort of irritates me every time. Partially because it's overly simplistic, but, even more so, because, while it's cute and humorous, it's not actually very good advice and it doesn't actually answer the question. No, you can't parse html with regex. But go look at the question. The author is just trying to detect some tags. That's not exactly parsing. It's true that there are some complications around things like "What if > appears in an attribute's value?" If you know your input well enough, or you don't need perfection, that might be a problem you can ignore. Alternatively, you can still use regex, if you use a sufficiently powerful regular expression tool. .NET's regular expressions, for example, have a concept of balancing groups that will let you do this. I would also point out that a lot of open source HTML parsing libraries are even more dangerous than regular expressions for parsing unknown HTML, because they use recursive descent. Where you have recursion, you have the potential for a stack overflow. With a regex library, you do have to be careful about catastrophic backtracking, but that's at least something you can usually handle in your own code, or, in the worst case, defend against with timeouts. A parser that's capable of blowing the call stack, and has been exposed to input from the Internet, though, is capable of taking down your process in a way you can't defend against in most languages. And it's difficult to patch up a parser like that without more-or-less rewriting it. I absolutely have had to deal with html handling code getting into situations like that in the past. Malicious input is real. So is plain old bad input. Reading the code before you use it is often a good idea.