FAQ Topic - How do I access a frame's content? (2009-10-25)

In comp.lang.javascript message <53e60b5e-ddec-4b97-aa14-64c31f883159@j1
9g2000yqk.googlegroups.com>, Sat, 31 Oct 2009 10:08:13, VK
<schools_ring (AT) yahoo (DOT) com> posted:

Dr J R Stockton wrote:
In effect, I want to read the file, HTML or TXT, as it exists on disc.

VK wrote:
You cannot do it for the reason explained at
http://groups.google.com/group/comp.lang.javascript/msg/d9f3f6724bada573

Dr J R Stockton wrote:
Unconvincing, because I *am* doing it,

VK wrote:
You don't, it is your delusion.
I don't know how and why are you doing it, but it was stated that "I
want to read the file, HTML or TXT, as it exists on disc." As long as
you are not using AJAX calls - and you don't - you are not able and
you are not reading any files "HTML or TXT, as it exists on disc" -
however wide the definition "as it exists on disc" would be taken.

Dr J R Stockton wrote:
Give or take irrelevant questions of character coding and newline
representation, I have been getting, by using innerHTML and by using
innerText, a string which agrees visually with the content of a TXT file
on disc, as would be shown by Notepad.

It should be expected in many (but not all) situations.
Contrary to the popular believe, browsers are *not* able to open text
or graphics files. What they are able to - as part of their extended
functionality - is to recognize some file types other than HTML and to
wrap them on the fly into predefined HTML templates so to display them
in the browser window. In the particular for text/plain files they are
using template
HTML
HEAD></HEAD
BODY
PRE> text file content goes here </PRE
/BODY
/HTML
with the exact tags' case (upper or lower) being browser dependent.

I wrote "getting, ..., a string", not "saw in a window".

Fram being a reference to an iframe recently loaded from a simple *.txt
file, the code

DIR = Fram.contentDocument.body
DIR = DIR.textContent || DIR.innerText // is latter needed? Yes, IE8
alert(DIR) // for VK

directly shows in the alert window plain text, not preceded by anything
using angle-brackets, for MS IE 8, Firefox 3.0.15, Opera 10.01, Safari
4.0.3, and Chrome 3.0. The <localhost> shown by Opera, and the
JavaScript shown by Safari, are parts of the alerts, not of their
contents.

This way the text you "see" is in effect the content of a single <pre
element necessarily altered from the "as it is on disc" to be placed
into this tag. For instance all less-than and greater-than signs will
be converted to the corresponding named HTML entities. The fact that
you were getting so far "by using innerHTML ..., a string which agrees
visually with the content of a TXT file" suggests that so far you were
lucky but not having any problematic characters in your .txt files,

"getting by using innerHTML" is not the same as "getting directly as
innerHTML". IIRC, most browsers wrapped with <pre> and one put rather
more at the top. When I was using innerHTML, I easily removed those by
RegExp.

Associated query : I have read a TXT file from disc, getting a matching
string. *It consists of many lines containing words separated by
punctuation. *They all start with the same sequence of words and
punctuation (improbably, zero length), but after that there is always
non-zero length. *No two lines completely agree. *What is the nicest way
of determining the common part AND obtaining in sequence strings for the
varying parts? *Think of it as like a representation of a directory
tree.

This is OT to the discussed FAQ topic but an interesting problem per
se. I am thinking to move it into separate thread or you may do it
yourself. I have a rather close request for ggNoSpam, in order to give
users an ability to adjust the regexp spam filter even with zero
knowledge of regular expressions. The abstract task description would
be:
"Given an array of strings with the minimum 2 and the maximum 1o
elements, find the shortest common word in these strings. If no such
common character sequence found, then try to find the biggest subset
of strings having a common word".

"word" is understood in regexp terms. To avoid "rush answers" with
common words like "a" or "the" articles let's define that the shortest
common word must be no shorter than 4 characters.

I've changed my mind about whether, for the present, I want to do that.
It would certainly increase efficiency, though perhaps not noticeably.
But doing that and the changes which would necessarily be associated
with it would be an impediment to extending capability in a direction
which may be possible and useful.

If such a thread is started, I'll participate, if anything worth writing
occurs to me.


var AoS = ["aaa bbb ccc ddd ccc bbb ddd", "bbb zzz ggg", "banana"]

var J, A, K, T, Obj = {}, Z = 0

J = AoS.length
while (J--) { T = {} // for each string
A = AoS[J].split(/\W+/) // make array of words
K = A.length ; while (K--) T[A[K]] = 1 // no internal dupes
for (K in T) Obj[K] ? Obj[K]++ : Obj[K] = 1 // ...
// ... if entry exists, increment, else create entry value 1
}

for (K in Obj) if (Obj[K]>Z) { Z = Obj[K] ; Word = [K, Z] }


Then Word[0] appears in Word[1] of the strings, and no word appears in
more than Word[1] of them.

The last line can be amended by making the test >= and complicating what
follows, to list all words of the highest popularity and not just the
first one found.

By using another variable

VERY SLIGHTLY TESTED (uses technique of LINXCHEK).

--
(c) John Stockton, nr London UK. ?@merlyn.demon.co.uk DOS 3.3, 6.20; WinXP.
Web <URL:http://www.merlyn.demon.co.uk/> - FAQqish topics, acronyms & links.
PAS EXE TXT ZIP via <URL:http://www.merlyn.demon.co.uk/programs/00index.htm>
My DOS <URL:http://www.merlyn.demon.co.uk/batfiles.htm> - also batprogs.htm.

Dr J R Stockton wrote:

In comp.lang.javascript message <hcdshu$ds2$1 (AT) news (DOT) eternal-
september.org>, Thu, 29 Oct 2009 22:11:19, Garrett Smith
dhtmlkitchen (AT) gmail (DOT) com> posted:
As long as I have something to say about it, the entry will correctly
explain how to access the window object of the IFRAME.


You are supposed, as FAQ maintainer, to be sustaining something useful
to the ordinary questioners, especially those who are not full-time
professional JavaScript programmers.

However, you appear entirely unable to understand their positions and
points of view. FAQ maintaining is a task for the sympathetic
communicator; not for the nerd.

A lot of the complaints with the FAQ is too verbose, too long.

The FAQ should not be too much of a chore to read. It should be easy
to understand.

Once the document is found, the next step is to do something with that,
right? That is what DOM and Forms section is for.

Things about the document seem more appropriate for "DOM and Forms", not
"window and frames".

Perhaps worth mentioning:-

The frame must be fully loaded before its content can be accessed.

fwin.document;// the document
fwin.document.documentElement; // root element.

See the section on DOM and Forms: #domRef

Perhaps worth another entry:-

How can I know when an iframe has loaded?

First, I'd rather edit/shorten the entry on #getWindowSize.

It is a long entry and explains a workaround for older versions of
Opera. It seems worth removing that workaround and its explanation.
That should shorten the entry considerably.

Less is more, here.
--
Garrett
comp.lang.javascript FAQ: http://jibbering.com/faq/

Dr J R Stockton wrote:

In comp.lang.javascript message <53e60b5e-ddec-4b97-aa14-64c31f883159@j1
9g2000yqk.googlegroups.com>, Sat, 31 Oct 2009 10:08:13, VK
schools_ring (AT) yahoo (DOT) com> posted:
Dr J R Stockton wrote:
In effect, I want to read the file, HTML or TXT, as it exists on disc.
VK wrote:
You cannot do it for the reason explained at
http://groups.google.com/group/comp.lang.javascript/msg/d9f3f6724bada573
Dr J R Stockton wrote:
Unconvincing, because I *am* doing it,
VK wrote:

[a lot of context]

This way the text you "see" is in effect the content of a single <pre
element necessarily altered from the "as it is on disc" to be placed
into this tag. For instance all less-than and greater-than signs will
be converted to the corresponding named HTML entities. The fact that
you were getting so far "by using innerHTML ..., a string which agrees
visually with the content of a TXT file" suggests that so far you were
lucky but not having any problematic characters in your .txt files,

"getting by using innerHTML" is not the same as "getting directly as
innerHTML". IIRC, most browsers wrapped with <pre> and one put rather
more at the top. When I was using innerHTML, I easily removed those by
RegExp.

You might try reading from the PRE element:

var fdoc = frames[0].document;
var pre = fdoc.getElementsByTagName("pre")[0];
var htmlString = pre.innerHTML;
var textString = (typeof pre.textContent == "string" ?
pre.textContent : pre.innerText);
--
Garrett
comp.lang.javascript FAQ: http://jibbering.com/faq/

In comp.lang.javascript message <hcjdqb$joa$1 (AT) news (DOT) eternal-
september.org>, Sat, 31 Oct 2009 23:36:41, Garrett Smith
<dhtmlkitchen (AT) gmail (DOT) com> posted:

You might try reading from the PRE element:

var fdoc = frames[0].document;
var pre = fdoc.getElementsByTagName("pre")[0];
var htmlString = pre.innerHTML;
var textString = (typeof pre.textContent == "string" ?
pre.textContent : pre.innerText);

As regards what I wanted to do, success is a matter of history. Fram is
the frame :

DIR = Fram.contentDocument.body
DIR = DIR.textContent || DIR.innerText // is latter needed? Yes, IE8

gives the content of the disc file; viewing alert(DIR) shows an exact
match to viewing the file in Notepad. That alert, commented out and
annotated VK, is in <URL:http://www.merlyn.demon.co.uk/linxchek.htm>.

OTOH, I cannot say what happens with non-Windows (indeed, with non-
XPsp3) systems - UNIX or Mac, for example ; and it would be helpful to
be able to give the necessary UNIX or Mac input to generate a suitable
file. Anyone like to try it in Mac or UNIX.

--
(c) John Stockton, nr London UK. ?@merlyn.demon.co.uk BP7, Delphi 3 & 2006.
<URL:http://www.merlyn.demon.co.uk/> TP/BP/Delphi/&c., FAQqy topics & links;
<URL:http://www.bancoems.com/CompLangPascalDelphiMisc-MiniFAQ.htm> clpdmFAQ;
NOT <URL:http://support.codegear.com/newsgroups/>: news:borland.* Guidelines

In comp.lang.javascript message <hcj02m$62n$1 (AT) news (DOT) eternal-
september.org>, Sat, 31 Oct 2009 19:42:12, Garrett Smith
<dhtmlkitchen (AT) gmail (DOT) com> posted:

Dr J R Stockton wrote:
In comp.lang.javascript message <hcdshu$ds2$1 (AT) news (DOT) eternal-
september.org>, Thu, 29 Oct 2009 22:11:19, Garrett Smith
dhtmlkitchen (AT) gmail (DOT) com> posted:
As long as I have something to say about it, the entry will correctly
explain how to access the window object of the IFRAME.

You are supposed, as FAQ maintainer, to be sustaining something
useful
to the ordinary questioners, especially those who are not full-time
professional JavaScript programmers.
However, you appear entirely unable to understand their positions
and
points of view. FAQ maintaining is a task for the sympathetic
communicator; not for the nerd.


A lot of the complaints with the FAQ is too verbose, too long.

The FAQ should not be too much of a chore to read. It should be easy
to understand.

Once the document is found, the next step is to do something with that,
right? That is what DOM and Forms section is for.

Things about the document seem more appropriate for "DOM and Forms", not
"window and frames".

For the FAQ to be useful to its intended readership, its Subjects (as
seen at the beginning) must be structured ENTIRELY from the point of
view of the questioner, without any consideration of the structure of
the answers.

Otherwise, you're writing a nerdy document much like the majority of the
big Flamingo book.

You MUST learn how the ordinary FAQ reader will think, when seeking an
answer.

Perhaps worth mentioning:-
| The frame must be fully loaded before its content can be accessed.

I am incompletely convinced of that. When reading by timeout, I thought
I saw signs of gaining access to an only partially-filled links array.
Certainly they might have been deceiving signs; but the point should be
checked in several actual browsers.

If your sentence were strictly true, one could issue a frame load
directly followed by a frame read, and the system would wait until
loaded before executing the read.

But it would be safe to write :-
Access to frame content should not be attempted before the frame is
fully loaded.

How can I know when an iframe has loaded?

Yes. I have success with the Fram.onLoad event in FF Op Sf Cr, but not
IE, where I seem to need to use a timeout. OTOH I suspect IE8 of lying
to me, or of being confused[*].

Flamingo wrote of a readyState property, which might be pollable.
[*] I get reports of many unused anchors in a file not containing those
anchors, in IE.

--
(c) John Stockton, Surrey, UK. ?@merlyn.demon.co.uk Turnpike v6.05 MIME.
Web <URL:http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, & links.
Proper <= 4-line sig. separator as above, a line exactly "-- " (SonOfRFC1036)
Do not Mail News to me. Before a reply, quote with ">" or "> " (SonOfRFC1036)

Dr J R Stockton :

Garrett Smith :

How can I know when an iframe has loaded?

Yes. I have success with the Fram.onLoad event in FF Op Sf Cr, but not
IE, where I seem to need to use a timeout. OTOH I suspect IE8 of lying
to me, or of being confused[*].

Flamingo wrote of a readyState property, which might be pollable.

I have no idea what Flamingo is, and also have no idea if the following
is acceptable for clj.
But here is a "solution" (with no setTimeout nor setInterval involved) I
am using since a long time with no issues (assuming, obviously, there is
no cross domain policy stuff) so far :

var frm = document.createElement('iframe');
var isLoaded = false;

function iframeOnLoad()
{
if ( !isLoaded )
{
alert('iframe content is loaded, ready to play with');
}
isLoaded = true;
}

function iframeOnReadyState()
{
if ( !isLoaded && this.readyState == "complete" )
{
iframeOnLoad();
}
}

frm.onload = iframeOnLoad;
frm.onreadystate = iframeOnReadyState;
frm.src = 'URL';

--
laurent

In comp.lang.javascript message <hcm6p4$5p2$1 (AT) news (DOT) eternal-
september.org>, Mon, 2 Nov 2009 00:54:58, Garrett Smith
<dhtmlkitchen (AT) gmail (DOT) com> posted:

Dr J R Stockton wrote:
In comp.lang.javascript message <hcj02m$62n$1 (AT) news (DOT) eternal-
september.org>, Sat, 31 Oct 2009 19:42:12, Garrett Smith
dhtmlkitchen (AT) gmail (DOT) com> posted:
Dr J R Stockton wrote:
In comp.lang.javascript message <hcdshu$ds2$1 (AT) news (DOT) eternal-
september.org>, Thu, 29 Oct 2009 22:11:19, Garrett Smith
dhtmlkitchen (AT) gmail (DOT) com> posted:
As long as I have something to say about it, the entry will correctly
explain how to access the window object of the IFRAME.

You are supposed, as FAQ maintainer, to be sustaining something
useful
to the ordinary questioners, especially those who are not full-time
professional JavaScript programmers.


Would an ASCII diagram for the FRAMES section help?

No. You seem not yet to have understood that, in a FAQ, the Subject
lines should represent what a questioner is likely to want to ask,
entirely independently of the nature of any possible solutions; and the
section belonging to each Subject line should provide what a questioner
needs to know, in a manner that he can understand and see to represent a
solution that he can use.

If you want to produce a document which, as a document, is structured to
reflect the internal structure of the ECMAScript language and the
browser DOM, then you should call it something other than a FAQ and let
someone more suitable handle the FAQ.

--
(c) John Stockton, nr London UK. ?@merlyn.demon.co.uk Turnpike v6.05 MIME.
<URL:http://www.merlyn.demon.co.uk/> TP/BP/Delphi/&c., FAQqy topics & links;
<URL:http://www.merlyn.demon.co.uk/clpb-faq.txt> RAH Prins : c.l.p.b mFAQ;
<URL:ftp://garbo.uwasa.fi/pc/link/tsfaqp.zip> Timo Salmi's Turbo Pascal FAQ.