No warning given for incorrect mime types in script tag

NEW
Unassigned

Status

()

P5
normal
15 years ago
4 months ago

People

(Reporter: bazkar, Unassigned)

Tracking

Trunk
x86
Windows XP
Points:
---

Firefox Tracking Flags

(Not tracked)

Details

(Reporter)

Description

15 years ago
User-Agent:       Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.1.4322)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6) Gecko/20040206 Firefox/0.8

When encountering a script tag in an incorrectly formatted MIME format, the 
browser just skips the script block without bringing up any message, warning or 
error in the console.
This might come in very handy when debugging a page that for instance has:
<script type="text\javascript">...</script>
instead of:
<script type="text/javascript">...</script>


Reproducible: Always
Steps to Reproduce:
1.
2.
3.



Expected Results:  
A warning (at least) in the console stating an incorrectly formatted MIME 
format in a script tag.

Updated

15 years ago
Assignee: firefox → parser
Component: General → HTML: Parser
Product: Firefox → Browser
Version: unspecified → Trunk
Status: UNCONFIRMED → NEW
Ever confirmed: true
This isn't handled in the HTML parser, and I don't think we should warn --
there's a LOT of vbscript out there and we would be warning on all of it.
Assignee: parser → general
Component: HTML: Parser → DOM
QA Contact: ian
There's also the issue that no one can figure out what the correct MIME-type for 
Javascript should be, and actually trying to deploy the correct MIME-type would
probably break things.
(Reporter)

Comment 3

15 years ago
(In reply to comment #2)
> There's also the issue that no one can figure out what the correct MIME-type 
for 
> Javascript should be, and actually trying to deploy the correct MIME-type 
would
> probably break things.

Maybe I should have stated my problem more clear. Althought the correct MIME 
type for Javascript is not defined clearly (mostly being either text/javascript 
or application/x-javascript), the syntax for defining MIME-types IS clearly 
defined (see: http://www.ietf.org/rfc/rfc2046.txt). So a warning can indeed be 
generated if a MIME-type is encountered that is not properly formatted. Mozilla 
does parse some aspect of the MIME type of a script tag as to known whether it 
should execute the code within the script. It shouldn't be that hard to 
generate a warning based on that parse when an incorrectly formatted MIME type 
is encountered. One cannot ofcourse generate warnings on all -not recognised or 
not executable MIME types- (such as text/vbscript as pointed out by Mr. 
Zbarsky) but MIME types that are simply not allowed can be warned about.

From http://www.ietf.org/rfc/rfc2046.txt:

The five discrete top-level media types are:
text, image, audio, video, application.
The two composite top-level media types are:
multipart, message.

Although no implications can be made about which types a script may or may not 
contain (ok, audio would seem really strange), a statement can be made about 
the MIME type foo+bar for instance to be false (since foo+bar is not one of the 
above mentioned allowed types and the syntax type/subtype is violated) and thus 
a warning can be generated.
> Mozilla does parse some aspect of the MIME type of a script tag

Not really.  It just does a straight case-insensitive compare of the part before
the ';' (if any) against each of the types we know we support; if it does not
match any of them we don't look at it.

So in fact, to do the sort of warning you want we'd need to write not only the
warning code but the parsing code.  Is it doable?  Yes.  Is it worth the code
complexity?  Probably not.
Assignee: general → nobody
QA Contact: ian → general
https://bugzilla.mozilla.org/show_bug.cgi?id=1472046

Move all DOM bugs that haven't been updated in more than 3 years and has no one currently assigned to P5.

If you have questions, please contact :mdaly.
Priority: -- → P5
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