HTMLArea Spell Checker



HTMLArea Spell Checker

The HTMLArea Spell Checker subsystem consists of the following
files:



spell-checker.js — the spell checker plugin interface for
HTMLArea

spell-checker-ui.html — the HTML code for the user
interface

spell-checker-ui.js — functionality of the user
interface

spell-checker-logic.cgi — Perl CGI script that checks a text
given through POST for spelling errors

spell-checker-style.css — style for mispelled words

lang/en.js — main language file (English).



Process overview


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
window.opener.SpellChecker.editor 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.


The server-side script (spell-check-logic.cgi)


Unicode safety — the program is
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). However, Aspell seems to not support Unicode
yet (thread concerning Aspell and Unicode).
This mean that words containing Unicode
characters that are not in 0..255 are likely to be reported as "mispelled" by Aspell.



Update: though I've never seen it mentioned
anywhere, it looks that Aspell does, in fact, speak
Unicode. Or else, maybe Text::Aspell does
transparent conversion; anyway, this new version of our
SpellChecker plugin is, as tests show so far, fully
Unicode-safe... well, probably the only 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.



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

The following Perl modules are required:


Text::Aspell
XML::DOM
CGI


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


Mihai Bazon

Last modified: Fri Jan 30 19:14:11 EET 2004