Comments on: What is typeof “unknown”? http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/ Web development and Internet trends Fri, 05 Dec 2008 10:47:17 +0000 http://wordpress.org/?v=2.6.1 By: fornetti http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-397991 fornetti Sat, 30 Aug 2008 20:31:07 +0000 http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-397991 I do not believe this I do not believe this

]]> By: Robert Nyman http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-8017 Robert Nyman Thu, 31 Aug 2006 18:07:07 +0000 http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-8017 Vojtech, Thanks for sharing! sudhakar, Interesting! Tom Trenka, Very interesting reading. However, it seems that that can't be applied to everything, given <a href="http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-5981" rel="nofollow">sudhakar's example</a> above. Vojtech,

Thanks for sharing!

sudhakar,

Interesting!

Tom Trenka,

Very interesting reading. However, it seems that that can’t be applied to everything, given sudhakar’s example above.

]]> By: Tom Trenka http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-8001 Tom Trenka Thu, 31 Aug 2006 13:59:54 +0000 http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-8001 Internet Explorer displays "unknown" when the object in question is on the other side of a COM+ bridge. You may not know this or realize this, but MS's XMLHTTP object is part of a different COM+ object that implements IUnknown; when you call methods on it, you're doing so over a COM bridge and not calling native JavaScript. Basically that's MS's answer if you try to test or access something that's not a true part of the JScript engine. Before you complain about it further, bear in mind that MSXML was designed to be used from any MS platform, including VB and C++; there are methods and properties on XMLHTTP that are useless in scripting and even cause some confusion (such as the much maligned onreadystate, which makes plenty of sense once you realize that MSXMLHTTP, when used from C++ and VB, give you full interactive access to the internal IStream via the responseStream property.) Internet Explorer displays “unknown” when the object in question is on the other side of a COM+ bridge. You may not know this or realize this, but MS’s XMLHTTP object is part of a different COM+ object that implements IUnknown; when you call methods on it, you’re doing so over a COM bridge and not calling native JavaScript.

Basically that’s MS’s answer if you try to test or access something that’s not a true part of the JScript engine.

Before you complain about it further, bear in mind that MSXML was designed to be used from any MS platform, including VB and C++; there are methods and properties on XMLHTTP that are useless in scripting and even cause some confusion (such as the much maligned onreadystate, which makes plenty of sense once you realize that MSXMLHTTP, when used from C++ and VB, give you full interactive access to the internal IStream via the responseStream property.)

]]> By: sudhakar http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-5981 sudhakar Wed, 12 Jul 2006 21:24:49 +0000 http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-5981 I also found that IE returns 'unknown' when using 'typeof'. It seems to happen in the following case: Add html form elements (such as textboxes, drop down lists etc.) to a container (such as a div) dynamically using javascript and then reset container's innerHTML to empty (div.innerHTML = ''). Repeat this again, this time selecting enabling/disabling a few of the html form elements. Next when you again add form elements to the DIV and try to access these elements by javascript, IE returns 'unknown' when using 'typeof'. I believe this has got some thing to do clearing these elements from IE's DOM. Apparently setting innerHTML = '' does not seem do this as IE could not figure out using 'typeof'. I also found that IE returns ‘unknown’ when using ‘typeof’.

It seems to happen in the following case:

Add HTML form elements (such as textboxes, drop down lists etc.) to a container (such as a div) dynamically using javascript and then reset container’s innerHTML to empty (div.innerHTML = ”).

Repeat this again, this time selecting enabling/disabling a few of the HTML form elements.

Next when you again add form elements to the DIV and try to access these elements by javascript, IE returns ‘unknown’ when using ‘typeof’.

I believe this has got some thing to do clearing these elements from IE’s DOM. Apparently setting innerHTML = ” does not seem do this as IE could not figure out using ‘typeof’.

]]> By: Vojtech http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-5430 Vojtech Tue, 13 Jun 2006 10:15:49 +0000 http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-5430 I met the "unknown" type when debugging one script working with an X3D Player. I had to write something like this: <code> function test(value) { if ((typeof value == "object") && (value == null)) {value = "null";} if (typeof value == "undefined") {value = "really_undefined";} if ((typeof value.toString == "undefined") || (typeof value.toString == "unknown")) {value = "no_toString";} return value + ":"; } </code> Without the third "if" I got "undefined" (no colon). I met the “unknown” type when debugging one script working with an X3D Player. I had to write something like this:

function test(value)
{
if ((typeof value == "object") && (value == null)) {value = "null";}
if (typeof value == "undefined") {value = "really_undefined";}
if ((typeof value.toString == "undefined") || (typeof value.toString == "unknown")) {value = "no_toString";}
return value + ":";
}

Without the third “if” I got “undefined” (no colon).

]]> By: Robert Nyman http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2157 Robert Nyman Thu, 22 Dec 2005 08:00:52 +0000 http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2157 Peter, Yes, maybe just a bug. However, the <code>open()</code> and <code>send()</code> methods do work, even though they also return typeof "unknown", as opposed to the <code>abort()</code> method that throws an error. Weird... Johan, Thanks for the idea, although the line that goes wrong is when I want to check for support for the <code>abort()</code> method. Peter,

Yes, maybe just a bug. However, the open() and send() methods do work, even though they also return typeof “unknown”, as opposed to the abort() method that throws an error.

Weird…

Johan,

Thanks for the idea, although the line that goes wrong is when I want to check for support for the abort() method.

]]> By: Johan http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2156 Johan Thu, 22 Dec 2005 03:48:34 +0000 http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2156 Maybe it is a syntax error typeof window.ActiveXObject != "undefined" rewrite as (boolean operator): typeof window.ActiveXObject !== undefined Maybe it is a syntax error

typeof window.ActiveXObject != “undefined”

rewrite as (boolean operator):

typeof window.ActiveXObject !== undefined

]]> By: Peter Leing http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2150 Peter Leing Wed, 21 Dec 2005 15:49:51 +0000 http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2150 Unless it is like Mats says, it may be a bug then. Microsoft's MSDN docs on Jscript only list the 6 typeof values you state. <a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/jscript7/html/jsoprtypeof.asp" rel="nofollow">JScript .NET typeof Operator</a> <a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/script56/html/ee8a1036-119f-486f-b034-b07bdba87f0c.asp" rel="nofollow">JScript typeof Operator (JScript 5.6)</a> I also tried the type of .open and .send and got the same 'undefined' message back. It may just be that trying to get the typeof from an ActiveXObject's Method is not supported or working. Unless it is like Mats says, it may be a bug then. Microsoft’s MSDN docs on Jscript only list the 6 typeof values you state.

JScript .NET typeof Operator

JScript typeof Operator (JScript 5.6)

I also tried the type of .open and .send and got the same ‘undefined’ message back. It may just be that trying to get the typeof from an ActiveXObject’s Method is not supported or working.

]]> By: Robert Nyman http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2149 Robert Nyman Wed, 21 Dec 2005 15:13:01 +0000 http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2149 Mats, Yes, it sounds like a "not implemented" thing, I've seen that one too. Rowan, Jens, Yeah, maybe I should change ad provider... :-) And yes, that web site looks pretty darn similar to the Mozilla web site. Peter, Yes, I've read that article, which is very good. And I guess his conclusion is right, that it's only necessary to abort calls in Mozilla. Anyway, it doesn't explain Microsoft's own interpretation of what <code>typeof</code> can return... :-) Mats,

Yes, it sounds like a “not implemented” thing, I’ve seen that one too.

Rowan, Jens,

Yeah, maybe I should change ad provider… :-)
And yes, that web site looks pretty darn similar to the Mozilla web site.

Peter,

Yes, I’ve read that article, which is very good. And I guess his conclusion is right, that it’s only necessary to abort calls in Mozilla.

Anyway, it doesn’t explain Microsoft’s own interpretation of what typeof can return… :-)

]]> By: Peter Leing http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2147 Peter Leing Wed, 21 Dec 2005 13:47:15 +0000 http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2147 Peter-Paul Koch had done some work with aborting XMLHTTP requests back in September. Maybe it will help you. <a href="http://www.quirksmode.org/blog/archives/2005/09/xmlhttp_notes_a_1.html" rel="nofollow">XMLHTTP notes: abort() and Mozilla bug</a> Peter-Paul Koch had done some work with aborting XMLHTTP requests back in September. Maybe it will help you.

XMLHTTP notes: abort() and Mozilla bug

]]> By: Jens Wedin http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2144 Jens Wedin Wed, 21 Dec 2005 12:54:51 +0000 http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2144 I know this does not have anyting to do with the article but I clicked the download now link. haha, what a joke, nice stealing from mozilla.org I know this does not have anyting to do with the article but I clicked the download now link. haha, what a joke, nice stealing from mozilla.org

]]> By: Rowan Lewis http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2141 Rowan Lewis Wed, 21 Dec 2005 11:04:40 +0000 http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2141 I wish I could help, but I can't :/ The reason I'm posting this is the ad under the article, it says: "INSTANT DOWNLOAD ! - Download right now!" Perhaps you should change ad provider... I wish I could help, but I can’t :/

The reason I’m posting this is the ad under the article, it says:

“INSTANT DOWNLOAD ! - Download right now!”

Perhaps you should change ad provider…

]]> By: Mats http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2140 Mats Wed, 21 Dec 2005 10:24:56 +0000 http://www.robertnyman.com/2005/12/21/what-is-typeof-unknown/#comment-2140 Maybe it's related to the "not implemented yet" type ... ;) I don't remember when I ran across it but I remember seeing it on one occasion. Maybe it’s related to the “not implemented yet” type … ;)

I don’t remember when I ran across it but I remember seeing it on one occasion.

]]>