190847 - document.styleSheets.item(String) should thrown an exception

Status: RESOLVED INVALID

(Core :: DOM: CSS Object Model, defect)

Description

[Vladimir Ermakov]

if you try to access document.styleSheets.item() with some string as a parameter
it returns the first style sheet. It should be throwing an exception

Comment 1

[Vladimir Ermakov]

Attachment: testcase

Comment 2

[Boris Zbarsky [:bzbarsky]]

hmm.... document.styleSheets.item(0) and document.styleSheet.item("heh") should
be equivalent -- the "heh" is cast to a number by the JS engine and its numeric
value is 0.

Not sure what Infinity and NaN are doing...

Comment 3

[Phil Schwartau]

In JavaScript, if the string 'hah' is coerced to a Number,
then NaN is the result:

js> Number('hah');
NaN

Whereas the empty string, or whitespace characters, get coerced to 0:

js> Number('');
0
js> Number('\n');
0
js> Number('\t');
0


Details: Section 9.3.1, "ToNumber Applied to the String Type"
ECMA-262 Edition 3 Final, http://www.mozilla.org/js/language

Comment 4

[Boris Zbarsky [:bzbarsky]]

So the question then is what NaN and Infinity get coerced to when passed through
XPConnect as an unsigned int....

Comment 5

[David Bradley]

XPConnect uses JS_ValueToECMAUint32. So what ever that API does for that
conversion, so will XPConnect, including failing if the function returns false.
The key is probably here: http://lxr.mozilla.org/seamonkey/source/js/src/jsnum.c#703

Comment 6

[Johnny Stenback (:jst)]

Mass-reassigning bugs to [e-mail]

Comment 7

[Cameron McCormack (:heycam)]

Web IDL says that "foo", NaN and Infinity all get converted to 0 when the type is "unsigned long" as it is for document.styleSheets.item().