html parsing and regular expressions

Anon

I did a search for this and found a guy with an unanswered post very much like this one. Here's the deal: I'm trying to make a php script parse html files to find links on the page. I am using the preg_ functions to do so. Currently my "find a link" pattern is:
$pattern = "/(?Ui)href\s=\s\"'(.).(php|html)[\"']/";

I then use this pattern in a preg_match_all function. This works ok, but I would like to improve it. I would like to use back references (http://www.php.net/manual/en/pcre.pattern.syntax.php#regexp.reference.back-references) so that it looks to close the href section with the same type of quotes that it opened with. That way href="...' would not match. The way the quotes are set up now, a line like a href="javascript:popUp('page.html')" would return href="javascript:popUp('. I know that a line like that wouldn't actually match because of the (?!javascript), but it's the best example I can come up with. I tried something like this:
$pattern = "/(?Ui)href\s=\s([\"'])(?!javascript🙂(.*).(php|html)\1/";

But that will not match anything at all. I tried \2 as well. Does anyone know how to get this going? Thanks for the help.

Anon

maybe a stupid point, but better ask twice:
did you use \1 or \1 as backreference?
rember that \ alone is the escape, so if you want \1 you rellay need to write \1 since it the pattern is in "..."

Anon

Thanks for the reply Reto. I did use just \1, but I tried \1 and it doesn't work either. This is what I tried:
$pattern = "/(?Ui)href\s=\s([\"'])(?!javascript🙂(.*).(php|html)\1]/";

It didn't match anything. I tried \2 as well. I'm pretty sure that you just want \1, if I'm reading the php manual page right. I think \1 is the right way to go, but something still isn't right.

Anon

I just realized I had an error in my code (extra ] at the end) when I tried the \1. Now it seems to work great, thanks Reto! I guess it makes sense that you would need the \ now that I think about it more. Thanks again.

Bad Code:
$pattern = "/(?Ui)href\s=\s([\"'])(?!javascript🙂(.*).(php|html)\1]/";

Good code:
$pattern = "/(?Ui)href\s=\s([\"'])(?!javascript🙂(.*).(php|html)\1/";