308004 - Quoted string containing </script> ends script

Status: RESOLVED DUPLICATE of bug 301847

(Core :: DOM: HTML Parser, defect)

Description

[Jerry Baker]

20050907 trunk

This has been happening for quite some time. Whenever I load Wired, there are
bits of JS strewn about the page. Investigation shows that Firefox is treating a
quoted string containing "</script>" as the real end of the script.

Anything inside of quoted strings should be ignored.

Comment 1

[Jerry Baker]

Attachment: Screen capture for those unable to see it.

Comment 2

[Jo Hermans]

I don't think so. The browser doesnt' know anything what's inside the <script>
block (it's just CDATA), so it's looking for the </script> tag directly.

Note that I don't see it at the moment, but that's probably because it's ad-related.

The author should do something like this :
document.write('<'); document.write('/script>');
because the spec requires that we stop processing when the first '</' is
encountered (see <http://www.w3.org/TR/html401/types.html#type-cdata>). But it
breaks so many pages, that we actually stop at '</script'. See bug 254606.

Comment 3

[Maarten Brak]

I agree that tags in quoted strings don't have to be ignored. However, i think
the following should work

<script type="text/javascript">
<![CDATA[
function test() { window.alert("</script>"); }
]]>
</script>

See also http://www.w3.org/TR/xhtml1/#h-4.8

Conclusion: content inside CDATA should not be parsed.

Comment 4

[Maarten Brak]

Of course, the point of my previous comment is, that the code example prints 
"); } ]]> to the screen, which should not happen.

Comment 5

[Blake Kaplan (:mrbkap) (inactive)]

This is a duplicate of either bug 301847 or bug 302469.

The workaround in comment 3 will only work in XHTML (not regular HTML, which
Wired sends). The htmlparser doesn't parse the JavaScript inside the <script>
tags (and thus cannot detect whether the </script> is inside a quoted string or
not. The easiest way to get around this is: document.write("<\/script>").

Comment 6

[Blake Kaplan (:mrbkap) (inactive)]

*** This bug has been marked as a duplicate of 301847 ***