Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.javascript > #26391 > unrolled thread

simple error

Back to article view | Back to comp.lang.javascript

Contents

  simple error Haris Bogdanovich <haris.bogdanovic@gmail.com> - 2014-12-28 18:12 +0100
    Re: simple error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-12-28 18:25 +0100
      Re: simple error "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2014-12-28 21:00 +0200
        Re: simple error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-12-28 21:32 +0100
          Re: simple error "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2014-12-28 23:56 +0200
    Re: simple error Denis McMahon <denismfmcmahon@gmail.com> - 2014-12-28 18:46 +0000
      Re: simple error "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2014-12-28 21:13 +0200
        Re: simple error Denis McMahon <denismfmcmahon@gmail.com> - 2014-12-28 23:19 +0000
          Re: simple error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-12-29 01:03 +0100
          Re: simple error "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-12-29 01:08 +0100
      Re: simple error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-12-28 20:13 +0100
        Re: simple error "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2014-12-28 22:30 +0200
          Re: simple error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-12-28 21:44 +0100
            Re: simple error "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2014-12-28 23:50 +0200
              Re: simple error "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-12-28 23:10 +0100
                Re: simple error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-12-29 03:10 +0100
                  Re: simple error "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-12-29 13:17 +0100
                    Re: simple error Tim Streater <timstreater@greenbee.net> - 2014-12-29 12:30 +0000
                      Re: simple error "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2014-12-29 14:49 +0200
                    Re: simple error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-12-29 15:18 +0100
                Re: simple error "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2014-12-29 08:20 +0200
                  Re: simple error "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-12-29 12:36 +0100
                    Re: simple error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-12-29 15:40 +0100
              Re: simple error Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-12-29 01:04 +0100
                Re: simple error "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2014-12-29 08:09 +0200

Page 1 of 2  [1] 2  Next page →

#26391 — simple error

Hi

<td onclick='this.innerHTML = 'X';'>--</td>

Why it won't change to X when I click on it ?

Thanks

[toc] | [next] | [standalone]

#26392

Haris Bogdanovich wrote:

> <td onclick='this.innerHTML = 'X';'>--</td>
> 
> Why it won't change to X when I click on it ?

Possibility: Assuming error correction, the resulting script code is

  this.innerHTML = X;

and the identifier “X” is not defined.  (See the error console.  See the FAQ  
for details on debugging.)

You must not use the same character as markup attribute value delimiter and 
script string value delimiter.  In this simple case, use either “'” and “"”, 
or “"” and “'”, respectively.  In other cases you can use a character 
reference or character entity reference to avoid the offending code, or you 
need to move the offending code elsewhere and use that from the attribute 
value.

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
Please do not cc me. / Bitte keine Kopien per E-Mail.

[toc] | [prev] | [next] | [standalone]

#26394

2014-12-28, 19:25, Lahn wrote:

> Haris Bogdanovich wrote:
>
>> <td onclick='this.innerHTML = 'X';'>--</td>
>>
>> Why it won't change to X when I click on it ?
>
> Possibility: Assuming error correction, the resulting script code is
>
>    this.innerHTML = X;
>
> and the identifier “X” is not defined.  (See the error console.  See the FAQ
> for details on debugging.)

Apparently Lahn did not bother actually looking at the error console. 
Should we bother looking at this “FAQ”, which he calls “the FAQ”?

In reality, as we can see using a browser’s Developer Tools, the code is 
parsed so that one attribute is

onclick="this.innerHTML = "

and another attribute is

x';'

with no value set. The latter is of course ignored, whereas the first 
one sets up an event handler that will terminate in an error (an 
assignment without right-hand-side).

An HTML validator issues several error messages about the construct. The 
error is really at the HTML markup level.

The problem is caused by an attempt to use the Ascii apostrophe (') 
inside an attribute value delimited by Ascii apostrophes. That just 
can’t work. There are various alternative ways to deal with this, such as

1) Use Ascii quotation marks (") as attribute value delimiters and Ascii 
apostrophes inside the value (as JavaScript string literal delimiters), 
or vice versa. E.g. "this.innerHTML = 'X';" or 'this.innerHTML = "X";'

2) Write the Ascii apostrophes inside the value using the reference 
&apos;, e.g. 'this.innerHTML = &apos;X&apos;;'

-- 
Yucca, http://www.cs.tut.fi/~jkorpela/

[toc] | [prev] | [next] | [standalone]

#26398

Jukka K. Korpela wrote:

> 2014-12-28, 19:25, Lahn wrote:
>> Haris Bogdanovich wrote:
>>> <td onclick='this.innerHTML = 'X';'>--</td>
>>>
>>> Why it won't change to X when I click on it ?
>>
>> Possibility: Assuming error correction, the resulting script code is
>>
>>    this.innerHTML = X;
>>
>> and the identifier “X” is not defined.  (See the error console.  See the
>> FAQ for details on debugging.)
> 
> Apparently Lahn did not bother actually looking at the error console.

Apparently you have no idea that observations in one browser version means 
nothing for all others, browsers and versions.  Hence there is no certainty, 
only “possibility”.

> Should we bother looking at this “FAQ”, which he calls “the FAQ”?

You should bother looking at it.

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
Please do not cc me. / Bitte keine Kopien per E-Mail.

[toc] | [prev] | [next] | [standalone]

#26401

2014-12-28, 22:32, Lahn wrote:

> Jukka K. Korpela wrote:
>
>> 2014-12-28, 19:25, Lahn wrote:
>>> Haris Bogdanovich wrote:
>>>> <td onclick='this.innerHTML = 'X';'>--</td>
>>>>
>>>> Why it won't change to X when I click on it ?
>>>
>>> Possibility: Assuming error correction, the resulting script code is
>>>
>>>     this.innerHTML = X;
>>>
>>> and the identifier “X” is not defined.  (See the error console.  See the
>>> FAQ for details on debugging.)
>>
>> Apparently Lahn did not bother actually looking at the error console.
>
> Apparently you have no idea that observations in one browser version means
> nothing for all others, browsers and versions.  Hence there is no certainty,
> only “possibility”.

If you actually knew HTML parsing rules instead of giving long lectures, 
you would know that your “possible” error correction cannot happen. 
There is no error in the first attribute specification, so it would be 
grossly inappropriate to “error correct” its value to something 
different. The second apostrophe terminates the attribute specification.

-- 
Yucca, http://www.cs.tut.fi/~jkorpela/

[toc] | [prev] | [next] | [standalone]

#26393

On Sun, 28 Dec 2014 18:12:19 +0100, Haris Bogdanovich wrote:

> Hi
> 
> <td onclick='this.innerHTML = 'X';'>--</td>
> 
> Why it won't change to X when I click on it ?

You're using single quotes (') to delimit a string inside a string 
delimited with single quotes. Use double quotes (") for one of the 
strings. (`) might also work (it does in my firefox at least).

-- 
Denis McMahon, denismfmcmahon@gmail.com

[toc] | [prev] | [next] | [standalone]

#26395

2014-12-28, 20:46, Denis McMahon kirjoitti:

> You're using single quotes (') to delimit a string inside a string
> delimited with single quotes.

Yes, that’s the problem here.

> Use double quotes (") for one of the strings.

That’s one solution.

> (`) might also work (it does in my firefox at least).

That’s not advisable. It does not work in other browsers, and it’s not 
described in any standard or reference. It seems to be a nonstandard 
feature in Firefox that grave accent (“backtick”, `) characters are 
recognized as string literal delimiters. This might be understandable as 
an attempt to deal with an assumed typing error (people often confuse 
small characters like this with each other). But I cannot imagine any 
context where it might be justifiable to utilize the feature.

-- 
Yucca, http://www.cs.tut.fi/~jkorpela/

[toc] | [prev] | [next] | [standalone]

#26404

On Sun, 28 Dec 2014 21:13:14 +0200, Jukka K. Korpela wrote:

> 2014-12-28, 20:46, Denis McMahon kirjoitti:
> 
>> You're using single quotes (') to delimit a string inside a string
>> delimited with single quotes.
> 
> Yes, that’s the problem here.
> 
>> Use double quotes (") for one of the strings.
> 
> That’s one solution.
> 
>> (`) might also work (it does in my firefox at least).
> 
> That’s not advisable. It does not work in other browsers, and it’s not
> described in any standard or reference. It seems to be a nonstandard
> feature in Firefox that grave accent (“backtick”, `) characters are
> recognized as string literal delimiters.

I wonder if that's a generic thing with the script engine in firefox.

Hmm, I also wonder if it's firefox, or the Os.

A quick test suggests it's at least the firefox scripting engine, rather 
than anything specific to element attributes.

http://www.sined.co.uk/tmp/this.htm

-- 
Denis McMahon, denismfmcmahon@gmail.com

[toc] | [prev] | [next] | [standalone]

#26406

Denis McMahon wrote:

> On Sun, 28 Dec 2014 21:13:14 +0200, Jukka K. Korpela wrote:
>> 2014-12-28, 20:46, Denis McMahon kirjoitti:
>>> (`) [to delimit one of the strings] might also work (it does in my 
>>> firefox at least).
>> 
>> That’s not advisable. It does not work in other browsers, and it’s not
>> described in any standard or reference. It seems to be a nonstandard
>> feature in Firefox that grave accent (“backtick”, `) characters are
>> recognized as string literal delimiters.
> 
> I wonder if that's a generic thing with the script engine in firefox.
> 
> Hmm, I also wonder if it's firefox, or the Os.
> 
> A quick test suggests it's at least the firefox scripting engine, rather
> than anything specific to element attributes.
> 
> http://www.sined.co.uk/tmp/this.htm

The standalone backtick is a syntax error in JavaScript (31) in Iceweasel 
31.3.0.

It is not in the latest working draft of ECMAScript Edition 6, where it 
delimits a template string:

<http://people.mozilla.org/~jorendorff/es6-draft.html#sec-template-literal-lexical-components>

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
Please do not cc me. / Bitte keine Kopien per E-Mail.

[toc] | [prev] | [next] | [standalone]

#26408

Denis McMahon wrote:

> On Sun, 28 Dec 2014 21:13:14 +0200, Jukka K. Korpela wrote:
> 
>> 2014-12-28, 20:46, Denis McMahon kirjoitti:
>>
>>> (`) might also work (it does in my firefox at least).
>>
>> That’s not advisable. It does not work in other browsers, and it’s not
>> described in any standard or reference. It seems to be a nonstandard
>> feature in Firefox that grave accent (“backtick”, `) characters are
>> recognized as string literal delimiters.
> 
> I wonder if that's a generic thing with the script engine in firefox.

I just found the explanation: "template literals" are an experimental
technology, part of the ECMAScript 6 proposal.[1][2]

[1]
<https://people.mozilla.org/~jorendorff/es6-draft.html#sec-template-literal-lexical-components>
[2]
<https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/template_strings>

-- 
Christoph M. Becker

[toc] | [prev] | [next] | [standalone]

#26396

Denis McMahon wrote:

> On Sun, 28 Dec 2014 18:12:19 +0100, Haris Bogdanovich wrote:
>> <td onclick='this.innerHTML = 'X';'>--</td>
>> 
>> Why it won't change to X when I click on it ?
> 
> […] Use double quotes (") for one of the strings.


> (`) might also work (it does in my firefox at least).

If so, only because of error correction.

<http://www.w3.org/TR/2014/REC-html5-20141028/syntax.html#before-attribute-value-state>

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
Please do not cc me. / Bitte keine Kopien per E-Mail.

[toc] | [prev] | [next] | [standalone]

#26397

2014-12-28, 21:13, Lahn wrote:

>> (`) might also work (it does in my firefox at least).
> If so, only because of error correction.
>
> <http://www.w3.org/TR/2014/REC-html5-20141028/syntax.html#before-attribute-value-state>

Of course, it has nothing to do with HTML error correction. Anyone who 
actually understands the elements of the basics of the fundamentals of 
HTML parsing, instead of showing off and making pointless “learned” 
lectures, knows that.

-- 
Yucca, http://www.cs.tut.fi/~jkorpela/

[toc] | [prev] | [next] | [standalone]

#26399

Jukka K. Korpela wrote:

> 2014-12-28, 21:13, Lahn wrote:
>>> (`) might also work (it does in my firefox at least).
>> If so, only because of error correction.
>>
>> <http://www.w3.org/TR/2014/REC-html5-20141028/syntax.html#before->> attribute-value-state>
> 
> Of course, it has nothing to do with HTML error correction. Anyone who
> actually understands the elements of the basics of the fundamentals of
> HTML parsing, instead of showing off and making pointless “learned”
> lectures, knows that.

The HTML5 parsing algorithm at least, which I cited, states that if a 
backtick (`) is parsed at this position, it constitutes a “Parse error”, 
that should be treated like “Anything else”, therefore “append[ed] […] to 
the current attribute’s value”.  This means it would become part of the 
attribute value.

An event-handler attribute value is parsed (per the definition of the 
default scripting language) as an ECMAScript /Program/.  But a backtick as 
first character of an ECMAScript /Program/ is a syntax error in ECMAScript 
implementations because it cannot be produced by production

| Program : SourceElements_opt

(assuming no syntax extensions).  Therefore, error correction would be 
necessary to execute that /Program/.

<http://ecma-international.org/ecma-262/5.1/#sec-14>

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
Please do not cc me. / Bitte keine Kopien per E-Mail.

[toc] | [prev] | [next] | [standalone]

#26400

2014-12-28, 22:44, Lahn wrote:

> The HTML5 parsing algorithm at least, which I cited, states that if a
> backtick (`) is parsed at this position, it constitutes a “Parse error”,

The issue was the use of the code

<td onclick='this.innerHTML = `X`;'>--</td>

which was stated to work in Firefox. (If you interpreted the description 
so that grave accents were used instead of outermost apostrophes, you 
did not pay attention. Such a construct does not work in Firefox, or any 
browser.)

There is no HTML error in that code. The error is in JavaScript code. 
JavaScript is a programming language discussed in this group, thought 
the resident troll regularly denies its existence.

The HTML attribute value is parsed without problems. The acute accent is 
just another character there.

-- 
Yucca, http://www.cs.tut.fi/~jkorpela/

[toc] | [prev] | [next] | [standalone]

#26402

Jukka K. Korpela wrote:

> The issue was the use of the code
> 
> <td onclick='this.innerHTML = `X`;'>--</td>
> 
> which was stated to work in Firefox.
> 
> There is no HTML error in that code. The error is in JavaScript code.

Obviously, not.  Otherwise it wouldn't work in Firefox' JavaScript
engine as if the backticks have been quotes.

> JavaScript is a programming language discussed in this group, thought
> the resident troll regularly denies its existence.

No, he does not.

-- 
Christoph M. Becker

[toc] | [prev] | [next] | [standalone]

#26409

Christoph M. Becker wrote:

> Jukka K. Korpela wrote:
>> JavaScript is a programming language discussed in this group, thought
>> the resident troll regularly denies its existence.
> 
> No, he does not.

Who is this “resident troll” you two are talking about anyway?

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
Please do not cc me. / Bitte keine Kopien per E-Mail.

[toc] | [prev] | [next] | [standalone]

#26415

Thomas 'PointedEars' Lahn wrote:

> Christoph M. Becker wrote:
> 
>> Jukka K. Korpela wrote:
>>> JavaScript is a programming language discussed in this group, thought
>>> the resident troll regularly denies its existence.
>>
>> No, he does not.
> 
> Who is this “resident troll” you two are talking about anyway?

Jukka frequently refers to you as "the resident troll".  I don't regard
you as such (on the contrary, but I'm weary of discussing this), but
anyhow, to my knowledge, *nobody* in this group denies the existence of
JavaScript.

-- 
Christoph M. Becker

[toc] | [prev] | [next] | [standalone]

#26416

In article <m7rgo6$ogb$1@solani.org>, Christoph M. Becker
<cmbecker69@arcor.de> wrote:

>Thomas 'PointedEars' Lahn wrote:
>
>> Christoph M. Becker wrote:
>> 
>>> Jukka K. Korpela wrote:
>>>> JavaScript is a programming language discussed in this group, thought
>>>> the resident troll regularly denies its existence.
>>>
>>> No, he does not.
>> 
>> Who is this “resident troll” you two are talking about anyway?
>
>Jukka frequently refers to you as "the resident troll".  I don't regard
>you as such (on the contrary, but I'm weary of discussing this), but
>anyhow, to my knowledge, *nobody* in this group denies the existence of
>JavaScript.

Agreed, but PointyHead has form in trying to assert that javascript
(and other variants of case) don't exist; he pushes this and other
matters that are equally trivially unimportant. That, and his tedious
pedantry and superciliousness, cause some to assess him as a troll.

-- 
"I love the way that Microsoft follows standards. 
 In much the same manner as fish follow migrating caribou."
                                               - Paul Tomblin, ASR

[toc] | [prev] | [next] | [standalone]

#26417

2014-12-29, 14:30, Tim Streater wrote:

> Agreed, but PointyHead has form in trying to assert that javascript
> (and other variants of case) don't exist;

Names of programming languages are case-insensitive in normal use, and 
also in abnormal use at large, except in you-know-what. So saying “there 
is no javascript” means denying the existence of the thing that most 
people call JavaScript, or javascript; it’s a different thing that by 
saying that, you-know-who tries to confuse people—making a statement 
that is simple and clear and trivially wrong, pretending to have made a 
statement about something “deeper”.

> he pushes this and other
> matters that are equally trivially unimportant. That, and his tedious
> pedantry and superciliousness, cause some to assess him as a troll.

Not to mention making factual mistakes in his pointless lectures. It is 
impossible, and unnecessary, to know which of the mistakes are 
intentional, meant to mislead people and trigger argumentation, and 
which are caused by his ignorance.

This thread has had its share of those mistakes.

-- 
Yucca, http://www.cs.tut.fi/~jkorpela/

[toc] | [prev] | [next] | [standalone]

#26418

Christoph M. Becker wrote:

> Thomas 'PointedEars' Lahn wrote:
>> Christoph M. Becker wrote:
>>> Jukka K. Korpela wrote:
>>>> JavaScript is a programming language discussed in this group, thought
>>>> the resident troll regularly denies its existence.
>>> No, he does not.
>> Who is this “resident troll” you two are talking about anyway?
> 
> Jukka frequently refers to you as "the resident troll".

He is only if one subscribes to that opinion.

HTH & F'up2 poster
 
-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
Please do not cc me. / Bitte keine Kopien per E-Mail.

[toc] | [prev] | [next] | [standalone]

Page 1 of 2  [1] 2  Next page →

Back to top | Article view | comp.lang.javascript

csiph-web