I think it is worth adding to this thread a quick explanation on why regular expressions are a very risky way to process HTML (as well as XML).

HTML is a very complex standard, the rules about what is a tag, how they can be ommited and infered, about whitespaces etc... are really complex.

Here are a list of proper meta tags that "naive" or even quite advanced regular expressions would fail to match (all are correctly parsed by HTML::TokeParser and I guess by HTML::TokeParser::Simple):

<meta  NAME="HTML.author" CONTENT="Joe Smith">    <!-- 2 spaces before
+ NAME -->
<meta NAME=HTML.author CONTENT="Joe Smith">       <!-- no " around the
+ value of NAME -->
<meta NAME="HTML.author" CONTENT='Joe Smith'>     <!-- you can use ' i
+nstead of " -->
<meta CONTENT="Joe Smith" NAME="HTML.author">     <!-- the order of at
+tributes is not significant -->
<meta NAME="HTML.author"
      CONTENT="Joe Smith">                        <!-- tags can span a
+ccross several lines-->
<meta NAME="HTML.author" CONTENT="Joe Smith" />   <!-- XHTML style -->

[download]

I am sure other examples could be found.

And of course you might grab things that look like a meta tag but are not, like:

<!-- <meta NAME="HTML.author" CONTENT="Joe Smith"> --> <!-- yep, a comment -->

In reply to Re: Fetching meta tag info by mirod
in thread Fetching meta tag info by Anonymous Monk

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