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Groups > comp.lang.javascript > #29394

Re: Give alert if form checkbox array is empty

From Stefan Weiss <krewecherl@gmail.com>
Newsgroups comp.lang.javascript
Subject Re: Give alert if form checkbox array is empty
Date 2016-01-21 12:17 +0100
Organization albasani.net
Message-ID <n7qeo5$g2i$1@news.albasani.net> (permalink)
References (1 earlier) <n7njvu$51k$1@news.albasani.net> <mu00ablmp9s6ronvrrejt2npfp5uffhpc5@4ax.com> <1851504.v7CTRd67sv@PointedEars.de> <n7pf3c$973$1@news.albasani.net> <9693913.xKMCTVlTbh@PointedEars.de>

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On 01/21/2016 08:54, Thomas 'PointedEars' Lahn wrote:
> Stefan Weiss wrote:
>> On 01/21/2016 00:59, Thomas 'PointedEars' Lahn wrote:
>>> You should familiarize yourself with the Array methods introduced with
>>> implementations of ECMAScript Edition 5 at the latest, in order to not
>>> write explicit loops where they are not necessary.  Examples have been
>>> given.
>>>
>>> Keep in mind that the built-in implementation of an algorithm is
>>> naturally always the most efficient one to use as it is, at best,
>>> provided in machine code already.
>>
>> Had you tested this, you would have discovered that your version - the
>> one with `[].slice.call(...)` - takes 2 to 17 times longer than the
>> simple loop, depending on the browser and which checkboxes are checked.
> 
> Irrelevant argument as that was _not_ what I as referring to.

Then what were you referring to? "Learn about built-in Array methods,
young padawan. Do not write explicit loops. Look at the example I
posted. Built-in algorithms are always faster. ... *handwave* These are
not the benchmarks you're looking for, move along."

> Besides, you are deliberately ignoring compilation here, but considering
> it elsewhere.

I never even mentioned compilation. Care to elaborate?

>> Also, storing `subjectTypes.length` in a variable has almost no benefit:
>> ...
> It has been shown in this newsgroup to be much more efficient in general.  
> Your test methodology is flawed.

Times change. What was once true about optimization can be obsoleted by
advancements in JS engine development, and in this case it has. Besides,
this is trivial to test. If you found a flaw in my tests (without even
seeing them), kindly point it out so we can discuss it.

>> Not that speed matters in this case - there are four checkboxes to test,
>> what kind of performance do you think we need for that? But you were
>> criticizing posted code for its performance and at the same time
>> advocating a slower and less readable version, so I thought you'd like
>> to know.
> 
> Your logic is flawed, too.

Let's see...
* Speed does not matter here - that one's pretty obvious.
* You talked about improving preformance of the posted code - check.
* You posted a slower version - check.
* You want to hear about this - ah, I think I found the flaw.


Again, performance is not an issue when checking four form elements in a
submit handler. The callback returns long before the user's finger has
lifted from the mouse button or enter key. But if you make speed an
issue anyway, don't be surprised when somebody calls you out on it.


- stefan

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Thread

Give alert if form checkbox array is empty Bunyip <bunyip@koalanet.com.au> - 2016-01-20 13:28 +1000
  Re: Give alert if form checkbox array is empty JJ <jj4public@vfemail.net> - 2016-01-20 12:30 +0700
    Re: Give alert if form checkbox array is empty Bunyip <bunyip@koalanet.com.au> - 2016-01-20 17:55 +1000
      Re: Give alert if form checkbox array is empty JJ <jj4public@vfemail.net> - 2016-01-20 19:29 +0700
        Re: Give alert if form checkbox array is empty "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2016-01-20 13:46 +0100
  Re: Give alert if form checkbox array is empty Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2016-01-20 08:23 +0000
    Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-20 15:52 +0100
      Re: Give alert if form checkbox array is empty Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2016-01-20 15:43 +0000
        Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-20 17:15 +0100
          Re: Give alert if form checkbox array is empty Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-01-20 17:53 +0000
            Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-20 20:39 +0100
              Re: Give alert if form checkbox array is empty Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2016-01-20 22:46 +0000
          Re: Give alert if form checkbox array is empty Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2016-01-21 07:53 +0000
            Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-21 10:52 +0100
              Re: Give alert if form checkbox array is empty Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2016-01-21 10:26 +0000
                Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-22 00:07 +0100
  Re: Give alert if form checkbox array is empty Stefan Weiss <krewecherl@gmail.com> - 2016-01-20 10:28 +0100
    Re: Give alert if form checkbox array is empty Bunyip <bunyip@koalanet.com.au> - 2016-01-21 08:05 +1000
      Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-21 00:59 +0100
        Re: Give alert if form checkbox array is empty Stefan Weiss <krewecherl@gmail.com> - 2016-01-21 03:17 +0100
          Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-21 08:54 +0100
            Re: Give alert if form checkbox array is empty Stefan Weiss <krewecherl@gmail.com> - 2016-01-21 12:17 +0100
        Re: Give alert if form checkbox array is empty John Harris <niam@jghnorth.org.uk.invalid> - 2016-01-21 14:16 +0000
        Re: Give alert if form checkbox array is empty Scott Sauyet <scott.sauyet@gmail.com> - 2016-01-21 19:52 -0800
          Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-22 09:48 +0100
            Re: Give alert if form checkbox array is empty Scott Sauyet <scott.sauyet@gmail.com> - 2016-01-22 10:45 -0800
              Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-23 19:41 +0100
                Re: Give alert if form checkbox array is empty Scott Sauyet <scott.sauyet@gmail.com> - 2016-01-24 17:51 -0800
                Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-25 19:46 +0100
                Re: Give alert if form checkbox array is empty Scott Sauyet <scott.sauyet@gmail.com> - 2016-01-27 11:09 -0800
        Re: Give alert if form checkbox array is empty Dr J R Stockton <reply1600@merlyn.demon.co.uk.invalid> - 2016-01-23 22:22 +0000
        Re: Give alert if form checkbox array is empty Scott Sauyet <scott.sauyet@gmail.com> - 2016-01-27 11:06 -0800
          Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-28 14:46 +0100
            Re: Give alert if form checkbox array is empty Gene Wirchenko <genew@telus.net> - 2016-01-28 10:30 -0800
              Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-28 20:06 +0100
                Re: Give alert if form checkbox array is empty Scott Sauyet <scott.sauyet@gmail.com> - 2016-01-28 23:32 -0800
                Re: Give alert if form checkbox array is empty "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2016-01-29 09:05 +0100
                Re: Give alert if form checkbox array is empty Scott Sauyet <scott.sauyet@gmail.com> - 2016-01-29 06:02 -0800
                Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-29 20:54 +0100
                Re: Give alert if form checkbox array is empty John Harris <niam@jghnorth.org.uk.invalid> - 2016-01-29 10:36 +0000
                Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-02-09 04:39 +0100
                Re: Give alert if form checkbox array is empty John Harris <niam@jghnorth.org.uk.invalid> - 2016-02-09 18:07 +0000
                Re: Give alert if form checkbox array is empty Gene Wirchenko <genew@telus.net> - 2016-01-29 09:32 -0800
                Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-29 20:34 +0100
                Re: Give alert if form checkbox array is empty Aleksandro <aleksandro@gmx.com> - 2016-01-29 16:50 -0300
                Re: Give alert if form checkbox array is empty Stefan Weiss <krewecherl@gmail.com> - 2016-01-30 03:31 +0100
                Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-30 04:19 +0100
                Re: Give alert if form checkbox array is empty Stefan Weiss <krewecherl@gmail.com> - 2016-01-30 05:01 +0100
              Re: Give alert if form checkbox array is empty Aleksandro <aleksandro@gmx.com> - 2016-01-28 16:39 -0300
            Re: Give alert if form checkbox array is empty Scott Sauyet <scott.sauyet@gmail.com> - 2016-01-29 06:04 -0800
              Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-29 20:54 +0100
                Re: Give alert if form checkbox array is empty Scott Sauyet <scott.sauyet@gmail.com> - 2016-01-29 14:55 -0800
                Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-30 04:55 +0100
                Re: Give alert if form checkbox array is empty Scott Sauyet <scott.sauyet@gmail.com> - 2016-01-30 15:48 -0800
                Re: Give alert if form checkbox array is empty Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-01-31 21:02 +0100
                Re: Give alert if form checkbox array is empty Scott Sauyet <scott.sauyet@gmail.com> - 2016-01-31 13:08 -0800
                Re: Give alert if form checkbox array is empty Andrew Poulos <ap_prog@hotmail.com> - 2016-02-01 12:28 +1100
                Re: Give alert if form checkbox array is empty Scott Sauyet <scott.sauyet@gmail.com> - 2016-02-01 17:58 -0800
  Re: Give alert if form checkbox array is empty "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2016-01-20 06:25 -0800
  Re: Give alert if form checkbox array is empty Aleksandro <aleksandro@gmx.com> - 2016-01-20 12:54 -0300

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