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Re: Recursive function to find a node in the DOM

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Il 07/19/2015 12:27 PM, Thomas 'PointedEars' Lahn ha scritto:

>
> See my correction.  You can use the getElementsByName(…) method for that; it
> is available on HTML document objects in implementations of W3C DOM Level 2
> HTML (since 2003) and HTML5.
>
> The getElementsByName(…) method is not available on element objects (at
> least not in a standards-compliant way; implementations may vary); however,
> the getElementsByTagName(…) method is, starting from IE/MSHTML 5.5 at the
> latest.  That method can be called as element.getElementsByTagName("*"), and
> the resulting NodeList can be filtered, if you do not want to be tied to a
> specific “tagName” property value.  If all else fails, the return value of
> document.getElementsByTagName("*") can be filtered.
>
> Higher Levels of the W3C DOM, implemented in recent Web layout engines,
> support other such methods that are more flexible, too:
> document.evaluate(…) for XPath queries, and document.querySelector(…) and
> document.querySelectorAll() for CSS queries.
>
>
> Also, you are reinventing the wheel.  Several common libraries provide such
> a function, by using a query engine or otherwise.  So I do not foresee many
> people being interested in your function.

OK, but I don't use any for now (apart the possibility I offer to have 
the photo gallery managed via jQuery + fancybox - if one absolutely 
wants that nice animation effect and is fine with the 100+ Kb of overhead).

>
> That said, I do not see why you would need this algorithm that finds an
> element by name in any context in the first place because there are more
> efficient built-in ones.  The “name” attribute is only allowed for the
> following element types (cf. [1] and [2]):
>
>    - “a” elements:
...
Many thanks, this is a very useful summary (and I will add it to my 
fragments of documentation i collect here and there). Very clear. But 
IIUC, I would need different functions for different elements, and maybe 
feature testing for getElementsByName...

>
>    - form controls:
>
>      There should not be form controls in an HTML document that are not part
>      of a form.  Only an ancestor “form” element guarantees proper validation
>      in HTML 5, and that this event works without client-side scripting
>      everywhere.  Controls of a specific form can be referred to by name
>      with document.forms[…].elements["…"].

As I said previously, if you have:

<html>
...
<form name... method=POST action...>
<INPUT TYPE=TEXT NAME=aName VALUE="blah">
</form>
...
</html>

and then you replace the <INPUT> element :
<script>
...
// oldEl is the element, obtained via gEBI or whatever
newEl=document.createElement("input");
newEl.name="aName";
newEl.type="file";
oldEl.parentNode.replaceChild(newEl,oldEl);

console.log(document.forms[0].aName.);
...
</script>

IE 7 (and IE 8 in compatibility mode) both show a gracious bug. At the 
time I made the test I wrote nodeFind(), that does not fail with any 
known [by me] browser. IIRC there were cross-browsers problems with 
getElementsByTagName at the time - not sure of that, anyway.

[apologize mode ON]
the fact is, I have to deal with my incomplete knowledge of different 
implementations of ECMAscript, different Levels of W3C DOM, different 
behaviour of different browsers and, in general, incomplete knowledge 
/per se/ :-), and the difficulty to keep up with the browser's 
evolution. Consequently, I try to avoid risks of cross-browsers 
incompatibility (and right now a new class of problems seems to arise 
with new devices such as smartphone, tablets and God knows what else: 
adaptive web design for one...). I must choose: and "the better is enemy 
of the good" (old italian proverb) has been proven to be a useful rule 
of thumb for me. I sometimes feel like an illiterate trying to write a 
poem, but I must do my best with the scarce resources I have (and this 
is true for me as for everyone else - just "scarce" has a different 
meaning).

JFC, here are some issues I remember I had to face in last years, apart 
the previously described one:
- getElementsByName/getElementsByTagName not implemented
- mysterios bug in Opera in printing a frame
- bug in Opera in iframes readystate
- bug in IE about the test for the existence of a method in designmode
- bug in Firefox if trying to get a specific property of a window
- try... catch not implemented
- the old problem of knowing if a page is completely loaded and rendered

...and so on, I can't remember all of them. :-)

[apologize mode OFF]

>>
>> I know of that. But it is not an exercise. The scenario here is: a user
>> can post a message in a [kinda of] message system. Messages can have
>> attachments. If the author wants to edit the message he posted, he may
>> want to change the text or the attachment. So he has a button "change
>> attachment", and the input showing the name of the actual attachment
>> becomes a <file> to select another one and upload it. :-)
>
> (“Exercise” was not to be understood verbatim.)  See my correction.  There
> appears to be no point to use a read-only input[type="text"] element here if
> you want to support IE/MSHTML because you need to replace the element in any
> case.

? Not sure to understand. If the user only wants to change a description 
in the form (that reflects the content of a record in a database), the 
<submit> sends the form with no <file> control, so the CGI server side 
only updates the record. If a <file> control is present the CGI takes a 
different route, uploads the file, stores the file somewhere and writes 
the address to the database etc.

>>>
>>> There is no “javascript”.
>>
>> ECMA, ok, ECMA.
>
> There is no ECMA (anymore).  There are Ecma International, and the
> ECMAScript Language Specification (named for historical reasons).  But what
> matters more than the name is the fact that this specification has several
> *different* implementations; several of them have “JavaScript” in their
> name.

I meant "ECMA" as string substitution of "java". I sould have written:
s/Java/ECMA/

>
> I do not know xbase.  ECMAScript is a language of the C family, so you need
> to return a value from a function if you want to avoid an implicit return
> value.  The implicit return value is the “undefined” value in ECMAScript
> implementations.

ACK. See also my answer to Scott Sauyet

Dan

-- 
"Everybody should pay taxes with a smile"
I tried, but they want money.

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Thread

Recursive function to find a node in the DOM "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-07-15 09:59 +0200
  Re: Recursive function to find a node in the DOM Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-07-15 11:59 +0200
    Re: Recursive function to find a node in the DOM Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-07-15 12:03 +0200
    Re: Recursive function to find a node in the DOM "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-07-15 13:36 +0200
      Re: Recursive function to find a node in the DOM Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-07-19 12:27 +0200
        Re: Recursive function to find a node in the DOM Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-07-19 12:34 +0200
        Re: Recursive function to find a node in the DOM "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-07-21 12:08 +0200
          Re: Recursive function to find a node in the DOM Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-07-25 14:11 +0200
            Re: Recursive function to find a node in the DOM "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-07-25 21:22 +0200
              Re: Recursive function to find a node in the DOM Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-07-27 16:12 +0200
    Re: Recursive function to find a node in the DOM "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-08-08 04:50 +0200
      Re: Recursive function to find a node in the DOM Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-08-08 09:33 +0200
        Re: Recursive function to find a node in the DOM "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-08-12 00:48 +0200
          Re: Recursive function to find a node in the DOM Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-08-12 01:18 +0200
            Re: Recursive function to find a node in the DOM "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-08-13 23:26 +0200
              Re: Recursive function to find a node in the DOM Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-08-16 08:48 +0200
                Re: Recursive function to find a node in the DOM "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-08-20 02:11 +0200
  Re: Recursive function to find a node in the DOM Scott Sauyet <scott.sauyet@gmail.com> - 2015-07-18 15:59 -0700
    Re: Recursive function to find a node in the DOM "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-07-21 12:30 +0200
      Re: Recursive function to find a node in the DOM Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-07-21 13:53 +0200
        Re: Recursive function to find a node in the DOM "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-07-21 14:51 +0200
          Re: Recursive function to find a node in the DOM Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-07-21 16:05 +0200
            Re: Recursive function to find a node in the DOM "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-07-21 20:35 +0200
            Re: Recursive function to find a node in the DOM Scott Sauyet <scott.sauyet@gmail.com> - 2015-07-30 22:10 -0700
              Re: Recursive function to find a node in the DOM "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-08-06 10:07 +0200
                Re: Recursive function to find a node in the DOM Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-08-06 20:15 +0200
                Re: Recursive function to find a node in the DOM "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-08-08 01:21 +0200
        Re: Recursive function to find a node in the DOM Scott Sauyet <scott.sauyet@gmail.com> - 2015-07-30 22:09 -0700
  Re: Recursive function to find a node in the DOM Denis McMahon <denismfmcmahon@gmail.com> - 2015-07-29 03:04 +0000
    Re: Recursive function to find a node in the DOM "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-08-06 10:20 +0200

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