JS as a teaching language

[Ben Crowell]

I teach physics at a community college, and ca. 2000 I experimented
with using python as a teaching tool. The point wasn't to teach
programming per se, but simply to give students a way of solving
problems numerically when there isn't any way to get a closed-form
solution using algebra or calculus. Other physics teachers have done
similar things using spreadsheets, but personally I think that's
a horrendous approach -- partly because spreadsheets aren't
standardized the way programming languages are, and partly because
spreadsheets aren't readable in the way that code is. I think my
experiment was partly successful and partly unsuccessful. I'm now
about to teach the same course again for the first time in a long
time, and am thinking about the possible merits of switching from
python to javascript. I'd be grateful for comments from anyone on
whether this seems like a good idea, or on certain aspects of what
I'm thinking of doing.

One hurdle I encountered with python was that I had to make sure
my students had access to a python interpreter. This meant downloading
a large application and installing it. This seems like a clear win
for js, since everyone who has firefox installed can run one-liners
in the console, and I would think it would be fairly straightforward
to supply a browser-based interface that would allow the user to
write simple javascript programs and run them.

It was also a nuisance in python that a computation as simple as
taking the square root of 2 required this much code:
import math
print math.sqrt(2.)
Also, it confused students that
print 2/3
gave 0 as its output. I found that many students were confused by
the significance of whitespace in python.

None of this was an insurmountable hurdle, but it
took up time and got in the way. (I remember in particular one
student, a middle-aged immigrant, who not only had never done any
computer programming, but didn't know how to hold a mouse.)

In js, the first example above becomes simpler:
Math.sqrt(2) ,
and the second one works as one naively expects.

I'm also thinking about the idea of making things a little easier
on the students by exposing some globals. For example, their own
code could run in an environment where the following has already
been done:
sqrt=Math.sqrt;
Thus they can simply do
sqrt(2)
and get an answer.

Are there any well-implemented, open-source, browser-based environments
for writing simple javascript programs? I would want to incorporate
such a thing as a component in some open-source courseware I've
written (http://www.lightandmatter.com/spotter/spotter.html), probably
using some ajaxy method for allowing the user to save his programs
on my server.

Thanks in advance for any advice or comments!

-Ben

[Andreas M.]

Am 15.10.2007 03:57 Randy Webb wrote

You should try it before being thankful. The proper one is alert, not
Alert. And you might find that javascript: is more successful than
jscript: is.

You should try them out yourself, before being so criticful ;-).
They work as advertised.

This is Microsoft InternetExplore r we are talking about and MS has its
own Javascript implementation, called JScript and JScript seems to be
case-insensitive.

For Firefox the right address-line would be (as you correctly indicated):

javascript:aler t(5*1.015)

(and the result would not be rounded)

But you knew that already. Or didn't you ;-)

--
Andreas M.

[David Mark]

On Oct 15, 5:15 am, "Andreas M." <foo...@invalid .invalidwrote:

Am 15.10.2007 03:57 Randy Webb wrote

You should try it before being thankful. The proper one is alert, not
Alert. And you might find that javascript: is more successful than
jscript: is.

You should try them out yourself, before being so criticful ;-).
They work as advertised.

This is Microsoft InternetExplore r we are talking about and MS has its

You are the only one talking about IE.

own Javascript implementation, called JScript and JScript seems to be
case-insensitive.

JScript is most assuredly case-sensitive. Regardless, alert (or Alert
as you call it) is a host object method, not part of the language.
The host object (window) has case-sensitive methods (as is the norm),
so window.Alert fails. Furthermore, I typed your jscript: example
into IE7's address bar and it did nothing.

[Dr J R Stockton]

In comp.lang.javas cript message <ieOdnX4sg8M1CY _anZ2dnUVZ_sejn Z2d@comcas
t.com>, Sun, 14 Oct 2007 17:17:42, McKirahan <Ne**@McKirahan .com>
posted:

>4.7 Why does simple decimal arithmetic give strange results?

For example, 5*1.015 does not give exactly 5.075 and 0.06+0.01
does not give exactly 0.07 in javascript.

<FAQENTRYOmit last two words.

In the CLJ FAQ, the topic is implicitly Javascript. Restating it may
suggest that the problem is unique to Javascript, which is not the case
(although it can be less obvious in some other languages).

--
(c) John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v6.05 IE 6
news:comp.lang. javascript FAQ <URL:http://www.jibbering.c om/faq/index.html>.
<URL:http://www.merlyn.demo n.co.uk/js-index.htmjscr maths, dates, sources.
<URL:http://www.merlyn.demo n.co.uk/TP/BP/Delphi/jscr/&c, FAQ items, links.

[Randy Webb]

Andreas M. said the following on 10/15/2007 5:15 AM:

Am 15.10.2007 03:57 Randy Webb wrote

>You should try it before being thankful. The proper one is alert, not
Alert. And you might find that javascript: is more successful than
jscript: is.

You should try them out yourself, before being so criticful ;-).
They work as advertised.

Maybe you would care to explain why the alert didn't work in MSIE7 until
I changed the Alert to alert and the jscript to javascript.

This is Microsoft InternetExplore r we are talking about and MS has its
own Javascript implementation, called JScript and JScript seems to be
case-insensitive.

Even testing again just now, it still won't give an Alert. And again,
changing it to alert and javascript gives me the alert.

For Firefox the right address-line would be (as you correctly indicated):

javascript:aler t(5*1.015)

(and the result would not be rounded)

But you knew that already. Or didn't you ;-)

Yes. And javascript:aler t(5*1.015) works in both. But you knew that
already. Or didn't you? ;-)

--
Randy
Chance Favors The Prepared Mind
comp.lang.javas cript FAQ - http://jibbering.com/faq/index.html
Javascript Best Practices - http://www.JavascriptToolbox.com/bestpractices/

[FAQEditor]

Dr J R Stockton said the following on 10/15/2007 12:25 PM:

In comp.lang.javas cript message <ieOdnX4sg8M1CY _anZ2dnUVZ_sejn Z2d@comcas
t.com>, Sun, 14 Oct 2007 17:17:42, McKirahan <Ne**@McKirahan .com>
posted:

>4.7 Why does simple decimal arithmetic give strange results?

For example, 5*1.015 does not give exactly 5.075 and 0.06+0.01
does not give exactly 0.07 in javascript.

<FAQENTRYOmit last two words.

If you omit them then it implies that it never gives it exactly and that
isn't true.

In the CLJ FAQ, the topic is implicitly Javascript. Restating it may
suggest that the problem is unique to Javascript, which is not the case
(although it can be less obvious in some other languages).

And not stating it implies it occurs in all languages and /that/ is not
true.

--
Randy
comp.lang.javas cript FAQ - http://jibbering.com/faq/index.html
FAQ Notes: http://www.jibbering.com/faq/faq_notes/faq_notes.html
ECMAScript Language Specification via FAQ2.6

[Dr J R Stockton]

In comp.lang.javas cript message <11************ **********@e34g 2000pro.go
oglegroups.com> , Mon, 15 Oct 2007 02:41:35, David Mark
<dm***********@ gmail.composted :

>This is Microsoft InternetExplore r we are talking about and MS has its

You are the only one talking about IE.

>own Javascript implementation, called JScript and JScript seems to be
case-insensitive.

JScript is most assuredly case-sensitive. Regardless, alert (or Alert
as you call it) is a host object method, not part of the language.
The host object (window) has case-sensitive methods (as is the norm),
so window.Alert fails. Furthermore, I typed your jscript: example
into IE7's address bar and it did nothing.

In the address bar, in IE6:

javascript:aler t(9) works as expected
jsCRipT:alert(9 ) ditto, but is changed to
vbscript:alert( 9) which works as line 1

In fact, all sorts of strange misspellings are accepted and converted to
either javascript: or vbscript: .

The language javascript is case-sensitive; but the language does not
contain the word javascript.

--
(c) John Stockton, Surrey, UK. ?@merlyn.demon. co.uk Turnpike v6.05 MIME.
Web <URL:http://www.merlyn.demo n.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)

[David Cox]

"Ben Crowell" <cr*******@ligh tSPAMandISmatte rEVIL.comwrote in message
news:47******** *************** @roadrunner.com ...

>I teach physics at a community college, and ca. 2000 I experimented
with using python as a teaching tool. The point wasn't to teach
programming per se, but simply to give students a way of solving
problems numerically when there isn't any way to get a closed-form
solution using algebra or calculus. Other physics teachers have done
similar things using spreadsheets, but personally I think that's
a horrendous approach -- partly because spreadsheets aren't
standardized the way programming languages are, and partly because
spreadsheets aren't readable in the way that code is. I think my
experiment was partly successful and partly unsuccessful. I'm now
about to teach the same course again for the first time in a long
time, and am thinking about the possible merits of switching from
python to javascript. I'd be grateful for comments from anyone on
whether this seems like a good idea, or on certain aspects of what
I'm thinking of doing.

One hurdle I encountered with python was that I had to make sure
my students had access to a python interpreter. This meant downloading
a large application and installing it. This seems like a clear win
for js, since everyone who has firefox installed can run one-liners
in the console, and I would think it would be fairly straightforward
to supply a browser-based interface that would allow the user to
write simple javascript programs and run them.

It was also a nuisance in python that a computation as simple as
taking the square root of 2 required this much code:
import math
print math.sqrt(2.)
Also, it confused students that
print 2/3
gave 0 as its output. I found that many students were confused by
the significance of whitespace in python.

None of this was an insurmountable hurdle, but it
took up time and got in the way. (I remember in particular one
student, a middle-aged immigrant, who not only had never done any
computer programming, but didn't know how to hold a mouse.)

In js, the first example above becomes simpler:
Math.sqrt(2) ,
and the second one works as one naively expects.

I'm also thinking about the idea of making things a little easier
on the students by exposing some globals. For example, their own
code could run in an environment where the following has already
been done:
sqrt=Math.sqrt;
Thus they can simply do
sqrt(2)
and get an answer.

Are there any well-implemented, open-source, browser-based environments
for writing simple javascript programs? I would want to incorporate
such a thing as a component in some open-source courseware I've
written (http://www.lightandmatter.com/spotter/spotter.html), probably
using some ajaxy method for allowing the user to save his programs
on my server.

Thanks in advance for any advice or comments!

-Ben

Just read through a weeks worth of this newsgroup to see the confusion
Javascript can bring to expert users. I think Javascript should only be
taught to people who want to learn Javascript, not as a tool for learning
something else.

Beginner's All-purpose Symbolic Instruction Code was written explicitly for
your purpose.

[Andreas M.]

Am 15.10.2007 11:41 David Mark wrote

You are the only one talking about IE.

Which browsers do support the vbscript: and jscript: protocols nativley
except IE? This is what we are talking about, so we are talking about IE.

JScript is most assuredly case-sensitive. Regardless, alert (or Alert
as you call it) is a host object method, not part of the language.

I do not call it "Alert". VBScript seems to call it that way. All I did
was to change the protocol in the uri within IE and it worked the same
as it did with the vbscript protocol. The reason I did so was, because
the original commentor was not interested in VBScript but Javascript, so
this was an obvious test to help him.

The host object (window) has case-sensitive methods (as is the norm),
so window.Alert fails. Furthermore, I typed your jscript: example
into IE7's address bar and it did nothing.

It works in IE6. This lead to my comment. Seems MS tightened the belt on
their whole WWW-pants with IE7.

--
Greetings,
Andreas M.

[Dr J R Stockton]

In comp.lang.javas cript message <2N************ *********@gigan ews.com>,
Mon, 15 Oct 2007 16:21:54, FAQEditor <cl****@comcast .netposted:

>Dr J R Stockton said the following on 10/15/2007 12:25 PM:

>In comp.lang.javas cript message <ieOdnX4sg8M1CY _anZ2dnUVZ_sejn Z2d@comcas
t.com>, Sun, 14 Oct 2007 17:17:42, McKirahan <Ne**@McKirahan .com>
posted:

>>4.7 Why does simple decimal arithmetic give strange results?

For example, 5*1.015 does not give exactly 5.075 and 0.06+0.01
does not give exactly 0.07 in javascript.

<FAQENTRYOmit last two words.

If you omit them then it implies that it never gives it exactly and
that isn't true.

No. The whole FAQ is talking about javascript. Any further emphasis on
javascript suggests that, in the current respect, javascript is unique
or nearly so.

>In the CLJ FAQ, the topic is implicitly Javascript. Restating it may
suggest that the problem is unique to Javascript, which is not the case
(although it can be less obvious in some other languages).

And not stating it implies it occurs in all languages and /that/ is not
true.

Not in educated English.

I suggest, though, that it does occur in most computer languages; though
many conceal it from the casual user by doing more rounding on
converting number to string.

--
(c) John Stockton, Surrey, UK. ??*@merlyn.demo n.co.uk Turnpike v6.05 MIME.
Web <URL:http://www.merlyn.demo n.co.uk/- FAQish topics, acronyms, & links.

Food expiry ambiguities: <URL:http://www.merlyn.demo n.co.uk/date2k-3.htm#Food>

[Peter Michaux]

On Oct 16, 5:06 am, Dr J R Stockton <[e-mail] mon.co.ukwrote:

In comp.lang.javas cript message <2NKdnd1blalCVo 7a4p2d...@gigan ews.com>,
Mon, 15 Oct 2007 16:21:54, FAQEditor <clj...@comcast .netposted:

Dr J R Stockton said the following on 10/15/2007 12:25 PM:

In comp.lang.javas cript message <ieOdnX4sg8M1CY _anZ2dnUVZ_sejn Z2d@comcas
t.com>, Sun, 14 Oct 2007 17:17:42, McKirahan <N...@McKirahan .com>
posted:

>4.7 Why does simple decimal arithmetic give strange results?

>For example, 5*1.015 does not give exactly 5.075 and 0.06+0.01
does not give exactly 0.07 in javascript.
<FAQENTRYOmit last two words.

If you omit them then it implies that it never gives it exactly and
that isn't true.

No. The whole FAQ is talking about javascript. Any further emphasis on
javascript suggests that, in the current respect, javascript is unique
or nearly so.

Have you ever heard about "never cry wolf"?

It is generous of Randy to maintain the FAQ and when something is just
a minor matter of author writing style how about just letting it be?
Otherwise the FAQ may loose it's maintainer.

Peter