[Javascript] Where to learn JS best practices & style

[Walter Torres]

Nice treatment on thhis subject David...

But I do have a followup question.

    document.formName.myobject.value

The above is great for FORM Objects.

What about non-FORM Objects? i.e: SPAN, P, H1, DIV, etc

Walter

> -----Original Message-----
> From: javascript-bounces at LaTech.edu
> [mailto:javascript-bounces at LaTech.edu]On Behalf Of David T. Lovering
> Sent: Saturday, March 29, 2003 1:13 AM
> To: [JavaScript List]
> Subject: Re: [Javascript] Where to learn JS best practices & style
>

> > are you saying that the statement "document.all.myobject.value" is more
> > efficiently expressed as "myobject.value"?
>
> document.all points to everything inside the document, which is a
> waste of CPU and memory to cache all the
> ID references.  It is only used to keep the DOM nazi's happy.
> Real people only use it when they want to
> confuse newbies.
>
> Leaving off the form identifier can be bad, and one should never
> take the 'document' preamble in vain.  Be
> a good DOMite, and try
>
>   document.formName.myobject.value, making appropriate name substitutions.
>
> >
> > how about document.all["obj" + lnJ++].value?  is there another way to
> > reference a contruct like that?
>
> Let me guess -- you must have been a C++ programmer in an earlier
> existence.
>
> If you REALLY want to go skating down all the elements inside a form, try
>
>   for (var i=0; i<document.myForm.elements.length; i++) {
>     var myElement = document.myForm.elements[i];
>     if (myElement.value != 'undefined') {
>       var myValue = myElement.value;
>     }
>   }
>
> Note that there are MANY JavaScript objects which are perfectly
> useful, but for
> which '.value' is potentially meaningless.  This checks to make
> sure you are dealing with a
> nice friendly object before it tries to suck up its value.
>
> >
> > how different is document.all.myobject.value from
> > myObjArray["row6"]["col5"].value?  Maybe i'm relying too much
> on VB/VFP's
> > object model where the dotted referencing is just the nomenclature for
> > explicitly stating the object heirarchy.  (aside from the fact
> that a DHTML
> > document doesn't really have a heirarchy)
>
> Quite different.  One is a static object, and the other is an
> array which requires unpacking.
>
> As to the 'correct' books to read -- rule #1: discard everything
> printed by Microsoft.
>
> Rule #2: Discard anything with the words 'Idiot' or 'Dummy' in the title.
>
> Rule #3: Anything which bills itself as the 'complete' JavaScript
> which is less than 3 inches thick
> can also be discarded.
>
> All levity aside, the three references I use most often are
>
> 	JavaScript Developer's Dictionary (SAMS)
>     PURE JavaScript (SAMS)
>     Professional JavaScript (2nd Edition) (Wrox)
>
> I would have recommended the JavaScript Bible, but the latest
> edition is nearly useless.
> If you can find a Third Edition, buy it, but otherwise stick to
> the other 3 books.  I do have about 200 others, but their utility
> is usually limited to one or two pet topics near and dear to the
> heart of their author.
>
> Also, when you see people leaving off prefixes like 'document'
> and 'window', rest assured that
> they are lazy bastards who will eventually be sent to the hot
> place and forced to reinsert them into
> the code written by other lazy bastards.
>
> >
> >   re: removing all the comments/short names- Are you suggesting that a
> > source-code be maintained with comments, and a production
> version without
> > comments?  Do you think the overhead of delivering in-line comments
> > outweighs the benefit of future readability/maintenance?  (consider the
> > target being an Intranet client with at least 10/100Mb
> wire-speed)  In this
> > same vein, do shorter (though perhaps less obvious) variable
> names improve
> > performance over more immediately readable (and somewhat
> "self-documenting")
> > variable naming conventions?  Isn't this why we've moved from 3rd to 4th
> > generation development languages?  By the time i've reduced my code to 3
> > character variable names without commenting, i might as well
> instantiate a
> > compiled object.
> >
>
> short names, particularly for temporary variables or indices are
> perfectly OK.
> The awkwardness is derived from describing the length of the text
> variable myFieldName
> in formA as merely being 'l'.  Five years from now you won't have
> a clue what 'l' is...
> whereas myFieldNameLength is perfectly obvious.
>
> I don't believe comments have any measurable impact on execution
> speed -- I believe
> the JavaScript in-line compiler nukes them before running the
> remaining code.  Anyone who
> wants to correct this naive delusion is welcome to step in anytime.
>
> -- Dave Lovering