The difference is that you don't filter--you convert. If you use an HTML-subset, you have to check for a multitude of different things, many of which may have only been mentioned in one sentance of one paragraph inside a whole heap of documentation. Missing one means that something you didn't want got through.

If you use a specifically-defined format (UBB tags come to mind), you get to specify exactly what goes in there and anything else is simply invalid. In this case, you can escape any HTML in the data (which is a lot easier than filtering specific kinds of HTML).

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send money to your kernel via the boot loader.. This and more wisdom available from Markov Hardburn.

In reply to Re^3: [Home Work]: Using (subset of) HTML as publishing language at PerlMonks: bug or feature? by hardburn
in thread [Home Work]: Using (subset of) HTML as publishing language at PerlMonks: bug or feature? by monsieur_champs

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.