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RE: xml parsing error for < character

From: Randy Waki <rwaki@flipdog.com>
Date: Fri, 1 Sep 2000 16:20:03 -0600
To: "Dave Raggett" <dsr@w3.org>, "cateen" <cateen@turboweb.net.au>
Cc: <html-tidy@w3.org>, <gerald@w3.org>
Message-ID: <001901c01462$c67ec080$51eee13f@rwaki>
Dave Raggett wrote:
>
> Unfortunately, current HTML browsers don't recognize CDATA marked
> sections, and furthermore they expect script elements to have
> CDATA content, and hence expect < and & to be unescaped.
>
> The XHTML 1.0 standard therefore recommends you move your scripts
> to external files. The onmouseover and other event attributes
> are however ok, as browsers will deal with entities in attribute
> values.
>
> In the future as true XHTML browsers are deployed this problem
> will go away, since when parsed as XML, you will be able to
> use script elements with &lt; for < or with the use of an
> enclosing CDATA marked section.
>
> I am uncertain as what HTML Tidy should do about this problem.
> If it wraps the contents of a script element in a CDATA marked
> section, it will stop the pages working in existing browsers.
> Ditto if it escapes the problem characters. It could write the
> contents of the script element to a new file, but what file
> name should it use?  One possibility is simply to warn if Tidy
> finds < and & within script elements, placing the burden on
> the user to decide how to deal with the problem.
>
> What do people think about this?

Dave,

For a partial solution, how about special-casing JavaScript and CSS, and
wrapping the CDATA section markup in JavaScript or CSS comments?  So far
this seems to be working for me.  This could be expanded to cover other
common cases like maybe VB Script.

The only flaw I know of is that an embedded occurrence of ]]> will end
the CDATA section prematurely.  If it occurred in a JavaScript string,
it could be broken up with a backslash, but I haven't attempted to do
this.

Here are the changes I'm using (tested in Java, translated to C).
They're based on a patch posted earlier by Gary L. Peskin.

--Randy

*** pprint.c    Fri Jul 28 17:57:56 2000
--- \temp\pprint.c      Fri Sep 01 15:46:21 2000
***************
*** 1244,1259 ****
          {
              PCondFlushLine(fout, indent);

              indent = 0;
-             PCondFlushLine(fout, indent);
              PPrintTag(lexer, fout, mode, indent, node);
              PFlushLine(fout, indent);

              for (content = node->content;
                      content != null;
                      content = content->next)
                  PPrintTree(fout, (mode | PREFORMATTED | NOWRAP |CDATA), indent,
lexer, content);

              PCondFlushLine(fout, indent);
              PPrintEndTag(fout, mode, indent, node);
              PFlushLine(fout, indent);
--- 1244,1337 ----
          {
              PCondFlushLine(fout, indent);

              indent = 0;
              PPrintTag(lexer, fout, mode, indent, node);
              PFlushLine(fout, indent);

+             Bool isJavaScript = no;
+             Bool isCSS = no;
+             AttVal *type = GetAttrByName(node, "type");
+             if (type != null)
+             {
+                 isJavaScript = wstrcmp(type->value, "text/javascript") == 0;
+                 isCSS = wstrcmp(type->value, "text/css") == 0;
+             }
+             if (xHTML && node->content != null)
+             {
+                 /* start a CDATA section for style and script content */
+                 /* NOTE: This won't work if the content contains "]]>" */
+
+                 /* disable wrapping */
+                 uint savewraplen = wraplen;
+                 wraplen = 0xFFFFFF;  /* a very large number */
+
+                 if (isJavaScript)
+                 {
+                     AddC('/', linelen++);
+                     AddC('/', linelen++);
+                 }
+                 else if (isCSS)
+                 {
+                     AddC('/', linelen++);
+                     AddC('*', linelen++);
+                 }
+                 AddC('<', linelen++);
+                 AddC('!', linelen++);
+                 AddC('[', linelen++);
+                 AddC('C', linelen++);
+                 AddC('D', linelen++);
+                 AddC('A', linelen++);
+                 AddC('T', linelen++);
+                 AddC('A', linelen++);
+                 AddC('[', linelen++);
+                 if (isCSS)
+                 {
+                     AddC('*', linelen++);
+                     AddC('/', linelen++);
+                 }
+                 PCondFlushLine(fout, indent);
+
+                 /* restore wrapping */
+                 wraplen = savewraplen;
+             }
+
              for (content = node->content;
                      content != null;
                      content = content->next)
                  PPrintTree(fout, (mode | PREFORMATTED | NOWRAP |CDATA), indent,
lexer, content);
+
+             if (xHTML && node->content != null)
+             {
+                 /* end the CDATA section for style and script content */
+
+                 /* disable wrapping */
+                 uint savewraplen = wraplen;
+                 wraplen = 0xFFFFFF;  /* a very large number */
+
+                 if (isJavaScript)
+                 {
+                     AddC('/', linelen++);
+                     AddC('/', linelen++);
+                 }
+                 else if (isCSS)
+                 {
+                     AddC('/', linelen++);
+                     AddC('*', linelen++);
+                 }
+                 AddC(']', linelen++);
+                 AddC(']', linelen++);
+                 AddC('>', linelen++);
+                 if (isCSS)
+                 {
+                     AddC('*', linelen++);
+                     AddC('/', linelen++);
+                 }
+                 PCondFlushLine(fout, indent);
+
+                 /* restore wrapping */
+                 wraplen = savewraplen;
+             }

              PCondFlushLine(fout, indent);
              PPrintEndTag(fout, mode, indent, node);
              PFlushLine(fout, indent);
Received on Friday, 1 September 2000 18:20:52 GMT

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