Reading RSS XML with IE

[Andrew Poulos]

When loading an rss feed into Windows IE, doc.childNodes. length always
equals 0. If I manually delete the <!DOCTYPE tag doc.childNodes. length
is correct.

I'm using
doc = new ActiveXObject(" Microsoft.XMLDO M");
to load the rss. Is this where the problem lies?

(Using document.implem entation.create Document with FF reads the XML
correctly with or without a DOCTYPE.)

Andrew Poulos

[Martin Honnen]

Andrew Poulos wrote:

When loading an rss feed into Windows IE, doc.childNodes. length always
equals 0. If I manually delete the <!DOCTYPE tag doc.childNodes. length
is correct.

I'm using
doc = new ActiveXObject(" Microsoft.XMLDO M");
to load the rss. Is this where the problem lies?

Hard to tell, we need to see more code, whether you load synchronously
or asynchronously.
Some settings to play with are
doc.resoveExter nals = false
doc.validateOnP arse = false
And how exactly does that !DOCTYPE declaration look like? Is the XML
valid in regard to that declared document type?
Have you checked
doc.parseError. errorCode
doc.parseError. reason

While Mozilla uses with Expat a non validating parser that ignores
externals resources IE uses MSXML and MSXML can validate against a DTD.
If you want to validate against the DTD then you need to check whether
there is a parseError.
--

Martin Honnen
http://JavaScript.FAQTs.com/

[Andrew Poulos]

Martin Honnen wrote:

Andrew Poulos wrote:

When loading an rss feed into Windows IE, doc.childNodes. length always
equals 0. If I manually delete the <!DOCTYPE tag doc.childNodes. length
is correct.

I'm using
doc = new ActiveXObject(" Microsoft.XMLDO M");
to load the rss. Is this where the problem lies?

Hard to tell, we need to see more code, whether you load synchronously
or asynchronously.
Some settings to play with are
doc.resoveExter nals = false
doc.validateOnP arse = false
And how exactly does that !DOCTYPE declaration look like? Is the XML
valid in regard to that declared document type?
Have you checked
doc.parseError. errorCode
doc.parseError. reason

Checking the error reason did it. I copied the RSS feed to my hard drive
and I must've inadvertently edited a tag name.

Andrew Poulos

[Andrew Poulos]

Andrew Poulos wrote:

Martin Honnen wrote:

Andrew Poulos wrote:

When loading an rss feed into Windows IE, doc.childNodes. length
always equals 0. If I manually delete the <!DOCTYPE tag
doc.childNodes. length is correct.

I'm using
doc = new ActiveXObject(" Microsoft.XMLDO M");
to load the rss. Is this where the problem lies?

Hard to tell, we need to see more code, whether you load synchronously
or asynchronously.
Some settings to play with are
doc.resoveExter nals = false
doc.validateOnP arse = false
And how exactly does that !DOCTYPE declaration look like? Is the XML
valid in regard to that declared document type?
Have you checked
doc.parseError. errorCode
doc.parseError. reason

Checking the error reason did it. I copied the RSS feed to my hard drive
and I must've inadvertently edited a tag name.

I spoke too soon. I tried parsing the RSS from this link:
<url: http://www.nasa.gov/rss/image_of_the_day.rss >
but IE tells me that "The element 'rss' is used but not declared in the
DTD/Schema."

This seems odd to me. Does this mean that the XML itself is invalid or
that there's some resource that I don't access to that is causing the
problem.

Andrew Poulos

[Duncan Booth]

Andrew Poulos wrote:

I spoke too soon. I tried parsing the RSS from this link:
<url: http://www.nasa.gov/rss/image_of_the_day.rss >
but IE tells me that "The element 'rss' is used but not declared in the
DTD/Schema."

This seems odd to me. Does this mean that the XML itself is invalid or
that there's some resource that I don't access to that is causing the
problem.

Yes, it means the XML is invalid.

The XML contains a DTD embedded inline in the document, but the DTD only
defines some entities & not any elements, so the document will fail to
validate. If you can turn off validation, or tell the parser to ignore the
inline DTD you may be handle it.

The simplest thing is probably to set the 'validateOnPars e' attribute to
false although this could hide more serious errors.

[VK]

Duncan Booth wrote:

Andrew Poulos wrote:

I spoke too soon. I tried parsing the RSS from this link:
<url: http://www.nasa.gov/rss/image_of_the_day.rss >
but IE tells me that "The element 'rss' is used but not declared in the
DTD/Schema."

This seems odd to me. Does this mean that the XML itself is invalid or
that there's some resource that I don't access to that is causing the
problem.

Yes, it means the XML is invalid.

The XML contains a DTD embedded inline in the document, but the DTD only
defines some entities & not any elements, so the document will fail to
validate. If you can turn off validation, or tell the parser to ignore the
inline DTD you may be handle it.

Did you try (IE-only):

<html>
<head>
<title>Untitl ed Document</title>
<meta http-equiv="Content-Type"
content="text/html; charset=iso-8859-1">
</head>

<body onload="alert(d ocument.scripts[0])">
<script type="text/xml"
src="http://www.nasa.gov/rss/image_of_the_da y.rss"></script>
</body>
</html>

That works just fine (means no parsing errors).

[Andrew Poulos]

VK wrote:

Duncan Booth wrote:

Andrew Poulos wrote:

I spoke too soon. I tried parsing the RSS from this link:
<url: http://www.nasa.gov/rss/image_of_the_day.rss >
but IE tells me that "The element 'rss' is used but not declared in the
DTD/Schema."

This seems odd to me. Does this mean that the XML itself is invalid or
that there's some resource that I don't access to that is causing the
problem.

Yes, it means the XML is invalid.

The XML contains a DTD embedded inline in the document, but the DTD only
defines some entities & not any elements, so the document will fail to
validate. If you can turn off validation, or tell the parser to ignore the
inline DTD you may be handle it.

Did you try (IE-only):

<html>
<head>
<title>Untitl ed Document</title>
<meta http-equiv="Content-Type"
content="text/html; charset=iso-8859-1">
</head>

<body onload="alert(d ocument.scripts[0])">
<script type="text/xml"
src="http://www.nasa.gov/rss/image_of_the_da y.rss"></script>
</body>
</html>

That works just fine (means no parsing errors).

I'm not sure what you're doing. How would I access nodes etc?

I'm using the activeX object to load the XML file so that I can later
walk it's DOM. I agree with Duncan Booth that the DTD fails to define
any ELEMENTS and so the XML is invalid.

Andrew Poulos

[Martin Honnen]

Andrew Poulos wrote:

I spoke too soon. I tried parsing the RSS from this link:
<url: http://www.nasa.gov/rss/image_of_the_day.rss >
but IE tells me that "The element 'rss' is used but not declared in the
DTD/Schema."

As already suggested you can set
xmlDocument.val idateOnParse = false;
before calling the load method and that way you can ensure that the DOM
is built if the XML is well-formed without being valid.

--

Martin Honnen
http://JavaScript.FAQTs.com/

[Andrew Poulos]

Martin Honnen wrote:

Andrew Poulos wrote:

I spoke too soon. I tried parsing the RSS from this link:
<url: http://www.nasa.gov/rss/image_of_the_day.rss >
but IE tells me that "The element 'rss' is used but not declared in
the DTD/Schema."

As already suggested you can set
xmlDocument.val idateOnParse = false;
before calling the load method and that way you can ensure that the DOM
is built if the XML is well-formed without being valid.

I used parseError.reas on to show me what was wrong with the sample RSS
XML I was testing and I didn't understand what this "new" error meant on
"real" RSS. I think I'll try to read the XML twice. If it fails trying
to validate the XML I'll try it without validating.

thanks
Andrew Poulos

[VK]

Andrew Poulos wrote:

<html>
<head>
<title>Untitl ed Document</title>
<meta http-equiv="Content-Type"
content="text/html; charset=iso-8859-1">
</head>

<body onload="alert(d ocument.scripts[0])">
<script type="text/xml"
src="http://www.nasa.gov/rss/image_of_the_da y.rss"></script>
</body>
</html>

I'm not sure what you're doing. How would I access nodes etc?
It is called "Dynamic Data Island" and it implants dynamic XML data
source into document. You're accessing data later (after script.onload)
using document.script s[i].XMLDocument + standard XML DOM methods.

Nevertheless it fails on the data source in question
"image_of_the_d ay.rss" for the same reason why responseXML is not set
simetimes: because RSS feed is *not* XML though it uses XML format. Its
MIME (if served properly) should be say "applicatio n/rss+xml" or other
(depending on what rss format is used: RSS, Atom). In any case nothing
similar to the needed "text/xml" as you can see. You need to have a
registered MIME in your browser (comes with installed RSS readers). Or
you have to read it as plain vanilla text and parse it manually - or
feed it manually to browser's XML parser.
DTD fails to define
any ELEMENTS and so the XML is invalid.

This sentence has no meaning for my humble mind. XML by definition can
consist of any proprietary nodes, as long as they paired properly. I
can use:
<foobar>
<foo>Foo</foo>
<bar>Bar</bar>
</foobar>

w/o any DTD "permission s" to use <foobar>, <foo>, <bar>

It fails because Content-Type doesn't match to the expected: "wants
text/xml, got application/rss+xml"