Getting Starting in JavaScript et al

[Gene Wirchenko]

Hello:

The company that I work for is going for a Web-based frontend for
its client billing system and to integrate the various company
databases and applications.

The app will be internal for the projected future. The browser
will be IE 9, the OS Windows 7. We will be using SQL Server Express
for the DBMS. For the Web end, it will be JavaScript, VBScript, ASP
Classic, and AJAX.

I have some sample code, but have already found deficiencies with
it. I have dealt with some of the deficiencies (escape characters was
a big one), but it has been a slow and arduous time.

I have found that there are many basic guides on the Web, but all
too few that get into the nasty bits. For example, escape characters
are not dealt by many pages, and I had to do a lot of hunting to find
out what to do.

I have read/skimmed the FAQ, and much of it is too high a level
for me for now.

Are there any gotchas that I should be particularly alert for?

Are there any good books that get into the nasty bits? (Of the
two mnetioned in the FAQ, one does not seem appropriate. The other
one, I am not sure about.)

You can read my questions as being about JavaScript specifically
or the conglomerate of systems I mentioned. I could use help with
both.

Sincerely,

Gene Wirchenko

 

[BOOK-AZ]

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[Erwin Moller]

Hello:

The company that I work for is going for a Web-based frontend for
its client billing system and to integrate the various company
databases and applications.

The app will be internal for the projected future. The browser
will be IE 9, the OS Windows 7. We will be using SQL Server Express
for the DBMS. For the Web end, it will be JavaScript, VBScript, ASP
Classic, and AJAX.

Hello Gene,

A few warnings:

VBscript ASP classic?
Are you sure about that?
I maintain some old software I wrote many years ago which is written in
classic VBscript on IIS, and it really hurts sometimes to wrap my mind
around it. I never use VBscipt/classic ASP anymore for new projects (it
has been like that for more than 10 years). Most developers won't use it
for new projects (unless it is the only thing they know).

Seriously, consider using something better since you give the impression
your company will develop it from the ground up anyway.

Also, make clear what you are doing serverside and clientside. In your
posting you give me the impression you are not sure where what language
runs exactly, but I might be wrong.
For example, both VBscript and JavaScript can run clientside and
serverside. If you are going to use AJAX, you must understand the
differences between serverside and clientside very well.
Especially if you are ever going to open up your webapp to the public:
security matters.

And last: Are you sure you want to support IE9 on Win7 only?
Good webapps run on any browser. Just make sure you write your code
sensible, and you support ALL BROWSERS worth mentioning.
I can't think of any valid reason to support only IE9 on Win7, unless
you are knee-deep into ActiveX components running inside the browser.
(Don't do that if you can avoid it.)

I have some sample code, but have already found deficiencies with
it. I have dealt with some of the deficiencies (escape characters was
a big one), but it has been a slow and arduous time.

Possibly.
In my experience it is easier to find poor scripts on the web than good
ones.
And it is hard for newcomers to tell them apart. :-(

I have found that there are many basic guides on the Web, but all
too few that get into the nasty bits. For example, escape characters
are not dealt by many pages, and I had to do a lot of hunting to find
out what to do.

Do you have an example of that?
I am not sure I can follow.
Are you talking about escaping characters like ' " \?

I have read/skimmed the FAQ, and much of it is too high a level
for me for now.

Yes, some topics are hard to grok (closures for example), but if you
plan to move your application to your customers, you must have a certain
understanding and do things right.
If you don't, your app will fail on other browsers or in circumstances
you cannot envision right now.
You also have the serious possibility of making serious mistakes and
create security holes.
If don't know what business you are in, or in which country you live,
but opening up private information can have serious repercussions in
certain countries. Please take care.

Are there any gotchas that I should be particularly alert for?

Yes. Too many to sum up here.

Are there any good books that get into the nasty bits? (Of the
two mnetioned in the FAQ, one does not seem appropriate. The other
one, I am not sure about.)

I learned my basics from the "Definitive Guide", second edition that was
I think, don't use that now. ;-)
I think I learned more by lurking around in comp.lang.javascript.

You can read my questions as being about JavaScript specifically
or the conglomerate of systems I mentioned. I could use help with
both.

To be honest: I think you should start studying a lot, or hire a
competent developer.

Last tip:
Always feel free to ask questions in here.
Don't be scared to get spanked in the beginning.
1) Post your examplecode/problem in here as clear as you can.
Don't be afraid to ask stupid questions.
2) You WILL be corrected, also on thing you didn't ask about.
Take it all seriously, ignore some trolls, and you'll be good.

Sincerely,

Gene Wirchenko

Good luck.
Regards,
Erwin Moller

 

[Gene Wirchenko]

A few warnings:

VBscript ASP classic?
Are you sure about that?

That is what has been selected.

I maintain some old software I wrote many years ago which is written in
classic VBscript on IIS, and it really hurts sometimes to wrap my mind
around it. I never use VBscipt/classic ASP anymore for new projects (it
has been like that for more than 10 years). Most developers won't use it
for new projects (unless it is the only thing they know).

Seriously, consider using something better since you give the impression
your company will develop it from the ground up anyway.

Your impression is correct.

Also, make clear what you are doing serverside and clientside. In your
posting you give me the impression you are not sure where what language
runs exactly, but I might be wrong.
For example, both VBscript and JavaScript can run clientside and
serverside. If you are going to use AJAX, you must understand the
differences between serverside and clientside very well.

It will be JavaScript on the client side and VBScript on the
server side.

Especially if you are ever going to open up your webapp to the public:
security matters.

I have been considering that.

And last: Are you sure you want to support IE9 on Win7 only?
Good webapps run on any browser. Just make sure you write your code
sensible, and you support ALL BROWSERS worth mentioning.
I can't think of any valid reason to support only IE9 on Win7, unless
you are knee-deep into ActiveX components running inside the browser.
(Don't do that if you can avoid it.)

I know your arguments. This is to be an internal app, and we can
enforce the platform. Later, we may expand it. It is more important
to get the app going first. I do not plan to write to IE9/Win7, but I
am not going to worry about breaking a different combo FOR NOW.
Personally, I prefer Firefox.

Possibly.
In my experience it is easier to find poor scripts on the web than good
ones.
And it is hard for newcomers to tell them apart. :-(

Code that will not properly handle values with single quotes or
ampersands are easy for this newcomer to detect. I have a solution to
this. I do not know that it is complete w.r.t. weird characters.

Do you have an example of that?
I am not sure I can follow.
Are you talking about escaping characters like ' " \?

That was one.

Yes, some topics are hard to grok (closures for example), but if you
plan to move your application to your customers, you must have a certain
understanding and do things right.
If you don't, your app will fail on other browsers or in circumstances
you cannot envision right now.
You also have the serious possibility of making serious mistakes and
create security holes.
If don't know what business you are in, or in which country you live,
but opening up private information can have serious repercussions in
certain countries. Please take care.

I plan to. This is an internal app though.

Yes. Too many to sum up here.

Can you give me some specifics? Even a checklist of "Not that,
you fool!" would help.

I learned my basics from the "Definitive Guide", second edition that was
I think, don't use that now. ;-)

That is the one I am not sure about. I will have to hunt down
some reviews. The FAQ has little.

I think I learned more by lurking around in comp.lang.javascript.

Yup. Did you know that there have been over 6,000 posts to this
newsgroup in the past two years? (Sorry, but that counts the nude
spams.)

To be honest: I think you should start studying a lot, or hire a
competent developer.

I am trying to study. As I mentioned earlier, there is a lot of
very basics, but not so much of the stuff needed to really make a
solid system.

Last tip:
Always feel free to ask questions in here.
Don't be scared to get spanked in the beginning.
1) Post your examplecode/problem in here as clear as you can.
Don't be afraid to ask stupid questions.
2) You WILL be corrected, also on thing you didn't ask about.
Take it all seriously, ignore some trolls, and you'll be good.

Standard, good USENET advice.

Thank you for your post.

Sincerely,

Gene Wirchenko

 

[Gene Wirchenko]

But what *are* your questions? You mention one thing ("escape

They are the sentences that end with "?". Here they are again:

Are there any gotchas that I should be particularly alert for?

Are there any good books that get into the nasty bits?

characters"), and I don't even understand, what you mean by this. If you

Maybe you use different terminology? In some languages, to
represent certain characters in a string, one must escape the
character. C example:
char tab='\t';
tab would then contain the tab character, not a backslash followed by
a lower-case T.

want answers, you should probably be asking clear questions.

One of the problems of getting started is finding out exactly
where to start. When I have specific questions, I will ask them. For
now, I am trying to get the lay of the land.

Sincerely,

Gene Wirchenko

 

[Thomas 'PointedEars' Lahn]

They are the sentences that end with "?". Here they are again:

Are there any gotchas that I should be particularly alert for?

Are there any good books that get into the nasty bits?

You are just asking for it:

<http://www.catb.org/~esr/faqs/smart-questions.html>


PointedEars

 

[Gene Wirchenko]

You are just asking for it:

<http://www.catb.org/~esr/faqs/smart-questions.html>

I was wondering if it were your past history with others or that
you were just plain rude. Unfortunately, your reply strongly suggests
it to be the latter.

Just in case the above gave you a bit of pause, how would you (as
a newbie) ask for a book on the subject of your newbieness that deals
with non-trivial uses?

Sincerely,

Gene Wirchenko

 

[Thomas 'PointedEars' Lahn]

I was wondering if it were your past history with others or that
you were just plain rude. Unfortunately, your reply strongly suggests
it to be the latter.

*PLONK*

 

[Elegie]

On 04/11/2011 04:41, Gene Wirchenko wrote :

Hi,

The app will be internal for the projected future. The browser
will be IE 9, the OS Windows 7. We will be using SQL Server Express
for the DBMS. For the Web end, it will be JavaScript, VBScript, ASP
Classic, and AJAX.

Others have already commented on that choice. Note that you can also use
ASP with JScript (this way you'd just have to learn one language instead
of two, unless you already know VBScript).

I used to do some ASP 3.0 about 10 years ago. I liked it very much, it
was very easy, yet be careful about your design: it's all too easy, with
ASP, to have your application layers interwoven (thus making your
application incredibly difficult to extend).

Are there any good books that get into the nasty bits? (Of the
two mnetioned in the FAQ, one does not seem appropriate. The other
one, I am not sure about.)

I don't know about books, but can tell you about my learning javascript.
It all began in 1999, I started with some big book about HTML/Javascript
(this gave me a feeling about the technology), then I started
participating on comp.lang.javascript. I soon identified posters whose
discussions and scripts looked interesting, and read all their past
posts. While doing so, I also read the specifications, and made some
test cases each time I encountered something new. In about 3 years, I
was pretty confident in my skills.

Authors I especially liked reading were Martin Honnen (I have never seen
this guy make a mistake), Jim Ley and Gosha Bine (the stereofrog), and a
few years later, Richard Cornford (who made decisive contributions to
the global understanding of the nature of javascript).

HTH,
Elegie.

 

[Clot Hears]

I was wondering if it were your past history with others or that
you were just plain rude. Unfortunately, your reply strongly suggests
it to be the latter.

It *is* the latter. But don't worry, he says that to *all* the girls.

 

[Elegie]

On 05/11/2011 05:14, Richard Cornford wrote :

Hi Richard,

For some reason the biggest "gotcha" with javascript is premature
confidence. There seem to be recurrent manifestations of the
Dunning-Kruger effect (if you are not familiar with than look it up as
it is an interesting, and all too human, psychological phenomenon).

<snip>

I did not know about it, but I like it very much. I believe I have seen
this many times (including in my own behavior), and will surely reuse that.

I recently tried and used the following to express similar ideas (but I
don't know if it was well-received):

"No knowledge is innocence, a bit of knowledge is obscurantism, a lot of
knowledge is wisdom".

Innocence is a blank page on which you can write things; it is also the
state before the mind becomes corrupted.

Obscurantism happens when you refuse to learn more and believe that what
you have learnt is right. When an innocent person first learns
something, and manages to put it in practice successfully, then he/she
will gain confidence in both what they have learnt and their ability to
learn. Success is sometimes worth less that failure, in that it can
hinders further learning.

Wisdom happens when you realize that the more you learn, the less you
know. It does not mean that your actual knowledge is shrinking (quite
the contrary), but rather that your horizon is expanding faster than you
learn. True wisdom is not about knowledge, but about attitude.

Recently I had to write a technical test for some JS programmer
interview. I tried to include every common misconception about
javascript that I have noticed. These are (most of) the points I tested
for that bset qualify as "gotchas":-

<snip>

This is an interesting idea. Experts usually judge a script by these
very criteria, so formulating a test requiring an explicit usage of them
by the candidate appears quite logical.

Regards,
Elegie.

 

[Sean Kinsey]

Really? ASP? In 2011?
Abstract this, and go for ASP.NET AJAX or WCF - it will solve _all_your potential problems with escaping and so forth.
To continue; it will even provide you with ready made Javascript proxy methods so that you can call any method as if they were local (although async).

If your management object to bringing in a 'new' technology - then tell them that it will be worth it (and I do know what I'm talking about).

Seriously, if they're in SF, let me now and I'll stop by and call them stupid.

 

[Evertjan.]

Sean Kinsey wrote on 05 nov 2011 in comp.lang.javascript:

Really? ASP? In 2011?

Classic ASP is marvelous, even in 2011.

You can do Javascript serverside using the same functions you built
clientside.

This will enhance your capability just by experencing one language.

And if you like vbs, so what?

 

[beegee]

Really? ASP? In 2011?
Abstract this, and go for ASP.NET AJAX or WCF - it will solve _all_your potential problems with escaping and so forth.
To continue; it will even provide you with ready made Javascript proxy methods so that you can call any method as if they were local (although async).

If your management object to bringing in a 'new' technology - then tell them that it will be worth it (and I do know what I'm talking about).

Seriously, if they're in SF, let me now and I'll stop by and call them stupid.

If they're in the NYC area, I will stop by and perform the same
service. If for no other reason, think of the future maintenance on
the project. If you do manage to hire programmers who are willing to
program in VBScript at all, they will curse you every step of the way.

If your company is dedicated to MS, which it sounds they are, go with
Sean's suggestions.

If you choose to ignore this advice, I suggest a third party AJAX
library, probably YUI since it has no syntactic sugar to hide the
javascript from newbies. IE9 lets you use the native HTTPRequest
object but management of your calls is still going to be an advanced
undertaking without a library.

Bob

 

[Richard Cornford]

<snip>

I did not know about it, but I like it very much. I believe I have
seen this many times (including in my own behavior), and will
surely reuse that.

<snip>

Yes, the lesson from these psychological phenomenon is that they
follow from having psychology, so from being human. We must all suffer
from them, or at least be vulnerable to them, and the only defence is
to be aware their existence and their tendency to drive us into
fooling ourselves. And then suspect our own positions and seek more
demonstrably objective justifications for them, or be willing to
abandon them in the face of not being able to find that objectivity.

<snip>

This is an interesting idea. Experts usually judge a script by these
very criteria, so formulating a test requiring an explicit usage of them
by the candidate appears quite logical.

In this area the test was more a matter being able to recognise (and
explain) the issues rather than actually use them. I wanted a test
that would straddle the knowledge boundary that I was interested in.
That worked in the sense that all of the candidates got most of the
questions wrong (with more than 50% getting zero). The depressing part
was that one of my colleagues noticed that I had effectively given the
answer to an HTTP question in the example mark-up for a previous XHTML
question, I decided to leave it and see what happened, and none of the
candidates spotted the connection.

Richard.

 

[Richard Cornford]

Really? ASP? In 2011?
Abstract this, and go for ASP.NET AJAX or WCF - it will solve
_all_your potential problems with escaping and so forth.
To continue; it will even provide you with ready made Javascript
proxy methods so that you can call any method as if they were
local (although async).

If your management object to bringing in a 'new' technology -
then tell them that it will be worth it (and I do know what
I'm talking about).

Seriously, if they're in SF, let me now and I'll stop by and
call them stupid.

Because people always react so openly to being called stupid?

Richard.

 

[Scott Sauyet]

Elegie wrote

[... re: the Dunning-Kruger effect ...]

I did not know about it, but I like it very much. I believe I have
seen this many times (including in my own behavior), and will
surely reuse that.

Yes, the lesson from these psychological phenomenon is that they
follow from having psychology, so from being human. We must all suffer
from them, or at least be vulnerable to them, and the only defence is
to be aware their existence and their tendency to drive us into
fooling ourselves.

Well, the lesson is not that clear. At least according to the
Wikipedia article [1], this is an American phenomenon, with a much
reduced effect for Europeans and a reversed version for Asians. I
haven't read the original paper, but the fact that it won the Ig Nobel
Prize for psychology in 2000 gives me pause about lending it too much
credence.

-- Scott

[1] http://en.wikipedia.org/wiki/Dunning–Kruger_effect

 

[Richard Cornford]

Elegie wrote

Richard Cornford wrote:
[... re: the Dunning-Kruger effect ...]
I did not know about it, but I like it very much. I believe I have
seen this many times (including in my own behavior), and will
surely reuse that.

Yes, the lesson from these psychological phenomenon is that they
follow from having psychology, so from being human. We must all
suffer from them, or at least be vulnerable to them, and the only
defence is to be aware their existence and their tendency to drive
us into fooling ourselves.

Well, the lesson is not that clear. At least according to the
Wikipedia article [1], this is an American phenomenon, with a much
reduced effect for Europeans and a reversed version for Asians.

Observing that there is a cultural bias in people's susceptibility to
a psychological phenomenon does not mean that any individual will
inevitably either be subject to it, or immune from it, due to their
cultural origin.

I haven't read the original paper, but the fact that it won the
Ig Nobel Prize for psychology in 2000 gives me pause about lending
it too much credence.

Being awarded an Ig Nobel Prize does not, of itself, reflect on the
quality/validity of that research.

"The Ig Nobel Prizes honor achievements that first make people laugh,
and then make them think. The prizes are intended to celebrate the
unusual, honor the imaginative and spur people's interest in science,
medicine, and technology."

Richard.

 

[Elegie]

On 08/11/2011 12:33, Richard Cornford wrote :

Hi,

In this area the test was more a matter being able to recognise (and
explain) the issues rather than actually use them. I wanted a test
that would straddle the knowledge boundary that I was interested in.
That worked in the sense that all of the candidates got most of the
questions wrong (with more than 50% getting zero). The depressing part
was that one of my colleagues noticed that I had effectively given the
answer to an HTTP question in the example mark-up for a previous XHTML
question, I decided to leave it and see what happened, and none of the
candidates spotted the connection.

I think that you need a drink It's too bad we don't live in the same
country, I'd bought you one with pleasure.

<follows drink talk>

Can you imagine an accountant who takes one day to perform a closing,
and another who takes a full month for that same closing? Well, in the
IT industry, that seems to be the case. In the "Mythical Man-Month",
Fred Brooks quoted a study which demonstrated that the skill level
between two programmers could range from 1 to 10; and I was told later
that the ratio was, nowadays, probably around 20 (I've got no study to
back this, though).

Of course, this difference can be attributed to other factors than
skill, such as creativity. Yet, this indicates that the industry is
still young, that methods are not well known (or even not well thought),
and that programmers are most often left on discovering good practices
rather learning them.

Consequences of this are dangerous: programmers not only are slow to
improve, but also believe "at all cost" in the knowledge they have
gained, even if they're wrong - because there was pain in it. I
currently believe that, even more than skills, it is attitude which
should matter: strong analytical skills, intellectual honesty,
curiosity, severity, ability to listen and comprehend, humility.

You know that I am no professional programmer (although I intend to
change that soon), but I do have some knowledge. However, I happened to
meet lots of professionals, and among them some "javascript experts".
Well, imagine how happy I was to learn that state-of-the-art javascript
now necessarily includes libraries which would use browser-detection,
favor function overloading and for..in loops as array iterators, extend
host and built-in objects (without even realizing that one should never
extend an external API) or even override their implementation, adopting
functional programming style at all cost...

To illustrate, I was recently told about that selector thing. I have not
researched it, so I may be wrong, but my initial (and so far, sole)
impression was not positive. Is the DOM API not flexible enough that it
needs further abstraction? To me, it really felt like kids having fun
building an interpreter (probably not even knowing what a token, a state
or a continuation actually are), and being forced to eventually /use/
it, well, because it'd be too bad to not use it, once it's been written.
(I'm probably unfair here.)

I see the path leading to expertise as follows:
- First, you're new to the technology, the code you write is pretty
simple. You read books and specifications, and test every bit of it
(trying obvious and not-so-obvious things). You're gradually reaching
step 2.
- You write more complicated code. You're enjoying the language, which
for javascript would translate as using loose-typing and reflective
techniques more than you should, trying to transform the language into
something you know (class-based inheritance, functional artifacts),
imagining how design patterns apply to the language. You have someone
read your code, he or she does not understand the least bit of it,
you're happy, but think you'd be happier if they had understood it.
- There comes a point when you yourself do not understand even more what
you have written. If you have some courage, you try and analyze it. Why
so complicated? Gradually, you write code which is becoming simpler and
simpler. Eventually, people reading your code will assess it as being
"clean", "obvious", "short" and "natural". You're not back to step 1,
but rather have reached elegance, i.e. you have understood the paradigm
of the language, and made it so that the language looks like it was made
for your program rather than the contrary.

Sorry for the rant! I believe that your story has reminded me of similar
events, and of the feelings I had then (feelings which I believe you
understand well).

Cheers,
Elegie.

 

[Gene Wirchenko]

On Tue, 8 Nov 2011 06:21:50 -0800 (PST), Richard Cornford

[snip]

Being awarded an Ig Nobel Prize does not, of itself, reflect on the
quality/validity of that research.

"The Ig Nobel Prizes honor achievements that first make people laugh,
and then make them think. The prizes are intended to celebrate the
unusual, honor the imaginative and spur people's interest in science,
medicine, and technology."

I have found the paper to have wonderful predictive value. It
explains a lot of behaviour that I have run into.

Sincerely,

Gene Wirchenko