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Groups > comp.lang.javascript > #17291

Re: getElementsByClassName: BUG in JS-engine?

From Mattias Campe <mattiaspuntcampe@geeeemeil.com>
Newsgroups comp.lang.javascript
Subject Re: getElementsByClassName: BUG in JS-engine?
Date 2012-11-18 14:56 +0100
Organization A noiseless patient Spider
Message-ID <50A8E917.3070303@geeeemeil.com> (permalink)
References <k8aee8$54m$1@dont-email.me> <50a8c202$0$6565$9b4e6d93@newsspool4.arcor-online.net>

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Op 18-11-12 12:09, Martin Honnen schreef:
> Most DOM collections are "live" collections so it is difficult iterating
> over them while manipulating them. Your loop manipulates the class of
> elements and that way the collection changes while the loop is executed
> and that leads to elements being skipped as after setting
>    alleOpvallendeAlineas[0].className
> that element is removed from the collection and the one that was at
> index 1 is now at index 0. And the next loop iteration changes
>    alleOpvallendeAlineas[1]
> which is the third element in the original collection.
>
> One way to avoid that problem is working from the end of the collection
> e.g.
>    for (var l = alleOpvallendeAlineas.length, i = l - 1; i >= 0; i--) {
>      alleOpvallendeAlineas[i].className = ...;
>    }

I wouldn't have found that explanation myself, but it all makes sense, 
once you know that :). So it's not a bug in the JS-engine after all ;).

Thank you very much for your fast and clear explanation!!

Kind regards
Mattias

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Thread

getElementsByClassName: BUG in JS-engine? Mattias Campe <mattiaspuntcampe@geeeemeil.com> - 2012-11-18 11:47 +0100
  Re: getElementsByClassName: BUG in JS-engine? Martin Honnen <mahotrash@yahoo.de> - 2012-11-18 12:09 +0100
    Re: getElementsByClassName: BUG in JS-engine? Mattias Campe <mattiaspuntcampe@geeeemeil.com> - 2012-11-18 14:56 +0100
      Re: getElementsByClassName: BUG in JS-engine? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-11-18 18:43 +0100

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