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    <title>HTMLArea Spell Checker</title>

    <h1>HTMLArea Spell Checker</h1>

    <p>The HTMLArea Spell Checker subsystem consists of the following


      <li>spell-checker.js &mdash; the spell checker plugin interface for

      <li>spell-checker-ui.html &mdash; the HTML code for the user

      <li>spell-checker-ui.js &mdash; functionality of the user

      <li>spell-checker-logic.cgi &mdash; Perl CGI script that checks a text
        given through POST for spelling errors</li>

      <li>spell-checker-style.css &mdash; style for mispelled words</li>

      <li>lang/en.js &mdash; main language file (English).</li>


    <h2>Process overview</h2>

      When an end-user clicks the "spell-check" button in the HTMLArea
      editor, a new window is opened with the URL of "spell-check-ui.html".
      This window initializes itself with the text found in the editor (uses
      <tt>window.opener.SpellChecker.editor</tt> global variable) and it
      submits the text to the server-side script "spell-check-logic.cgi".
      The target of the FORM is an inline frame which is used both to
      display the text and correcting.

      Further, spell-check-logic.cgi calls Aspell for each portion of plain
      text found in the given HTML.  It rebuilds an HTML file that contains
      clear marks of which words are incorrect, along with suggestions for
      each of them.  This file is then loaded in the inline frame.  Upon
      loading, a JavaScript function from "spell-check-ui.js" is called.
      This function will retrieve all mispelled words from the HTML of the
      iframe and will setup the user interface so that it allows correction.

    <h2>The server-side script (spell-check-logic.cgi)</h2>

      <strong>Unicode safety</strong> &mdash; the program <em>is</em>
      Unicode safe.  HTML entities are expanded into their corresponding
      Unicode characters.  These characters will be matched as part of the
      word passed to Aspell.  All texts passed to Aspell are in Unicode
      (when appropriate).  <strike>However, Aspell seems to not support Unicode
      yet (<a
        href="http://mail.gnu.org/archive/html/aspell-user/2000-11/msg00007.html">thread concerning Aspell and Unicode</a>).
      This mean that words containing Unicode
      characters that are not in 0..255 are likely to be reported as "mispelled" by Aspell.</strike>

      <strong style="font-variant: small-caps; color:
      red;">Update:</strong> though I've never seen it mentioned
      anywhere, it looks that Aspell <em>does</em>, in fact, speak
      Unicode.  Or else, maybe <code>Text::Aspell</code> does
      transparent conversion; anyway, this new version of our
      SpellChecker plugin is, as tests show so far, fully
      Unicode-safe... well, probably the <em>only</em> freeware
      Web-based spell-checker which happens to have Unicode support.

      The Perl Unicode manual (man perluniintro) states:

        Starting from Perl 5.6.0, Perl has had the capacity to handle Unicode
        natively.  Perl 5.8.0, however, is the first recommended release for
        serious Unicode work.  The maintenance release 5.6.1 fixed many of the
        problems of the initial Unicode implementation, but for example regular
        expressions still do not work with Unicode in 5.6.1.

    <p>In other words, do <em>not</em> assume that this script is
      Unicode-safe on Perl interpreters older than 5.8.0.</p>

    <p>The following Perl modules are required:</p>

      <li><a href="http://search.cpan.org/search?query=Text%3A%3AAspell&mode=all" target="_blank">Text::Aspell</a></li>
      <li><a href="http://search.cpan.org/search?query=XML%3A%3ADOM&mode=all" target="_blank">XML::DOM</a></li>
      <li><a href="http://search.cpan.org/search?query=CGI&mode=all" target="_blank">CGI</a></li>

    <p>Of these, only Text::Aspell might need to be installed manually.  The
      others are likely to be available by default in most Perl distributions.</p>

    <hr />
    <address><a href="http://dynarch.com/mishoo/">Mihai Bazon</a></address>
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