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Groups > comp.lang.javascript > #28465

Re: Move a div with mouse

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Il 07/24/2015 08:36 PM, Thomas 'PointedEars' Lahn ha scritto:
> danca (Daniele Campagna) wrote:
>
>> I needed to solve an old stupid issue regarding an <iframe> (aka a <div>
>> containing an <iframe>) that sometimes is misplaced in a page [served by
...
>>
>> After many hours searching, studying, testing and tinkering with Firefox
>> and IE I ended up with this function:
>
> First of all, your code (style) is barely readable.  If you want others to
> review your code, you should employ a code style that is easily readable.
> A decent code editor can help with that.

:-(

>
> Particularly for Usenet, you should post code that still works when word-
> wrapped at about the 72th text column.  See the FAQ.

I TRIED to copy-and-paste and then to adjust the [horrible] result.

>
>> // usage: makeMovable(<id of the div to drag>,<optional id of a
>> "handler" (f.e. a small image inside the div) to drag the div>)
>
> This code was word-wrapped by your newsreader and does not work anymore
> because of that.  It would not have happened had you used /*… */ instead,
> which I recommend for documentation comments.
>

OK.

>> var makeMovable = function(target, handle) {
>>    target = document.getElementById(target);
>>    if (!handle) handle = target; else
>>    handle=document.getElementById(handle); if (document.addEventListener){
>>
>> handle.addEventListener("mousedown",function(event){e=event||
> window.event;if
>> (e.preventDefault) e.preventDefault(); else e.returnValue = false;})
>
> Wrong.  You are testing “document.addEventListener”, but you are calling
> “handle.addEventListener” – a different method.  Test exactly that which you
> will be using, and test for callable objects to be callable, not merely
> existing.  In particular, do not subject methods of host objects to simple
> type-converting tests; this is error-prone (search for “isHostMethod”).

So it is not correct to infer[It exists? I mean make a deduction] that 
if document.addEventListener does not exist <something>.addEventListener 
couldn't instead exist? Hummmmm...
(Ubi major minus cessat).

>
>>    }else{
>>
>> handle.attachEvent("onmousedown",function(event){e=event||window.event;if
>> (e.preventDefault) e.preventDefault(); else e.returnValue = false; })
>>    }
>>    handle.onmousedown = function(event) {
>
> It makes no sense to use one of EventTarget::addEVentListener() from the W3C
> DOM and eventTarget.attachEvent() from the MSHTML DOM, *and* subsequently
> EventTarget::onmousedown from the Netscape/HTML5 DOM.  See my tests about
> the side effects of using both from earlier this year, and
> jsx.dom.addEventListener() for the correct approach.

OMG. Ok, I'll take a look.

>
>> […]
>>     }else{ alert("no event")// just in case}
>
> This may be a syntax error.  Your code is so unreadable that it is difficult
> to tell without copying and reformatting it.
>
>>     document.onmouseup = function() {
>>      document.onmousemove = null;
>>      document.onmouseup = null;
>>     }
>
> Nonsense.

Ehm... it should cancel the event listeners - and it seems to work in IE 
and FF. What's wrong with canceling eventListeners that simple way?

>
>> […]
>> So, JFC,
>
> You want to refrain from cursing when asking a question.
>
> See also <http://www.catb.org/~esr/faqs/smart-questions.html>.
>
>> why this does not work with those 2 browsers?
>
> You are still under the misconception that it would be prudent to think in
> terms of browsers instead of DOM implementations.
>

NoNo, I am not thinking at all. I just reported the thing. What the 
hell, I didn't tried browser sniffing at all, and I simply can't imagine 
what feature detection I should put on to distinguish between the 
[working] IE and FF and the [aliens] Chrome and Safari.

I exhausted all my thinking capabilities in the hours I tried to make it 
work. Now I am void of ideas - and this is the reason I bother people in 
this NG.

Anyway thanks for your time - but, an idea about the fact that Chrome 
and Safari seem to dislike my code is still to come, while an idea about 
why you dislike it has been clearly expressed. :-)

Dan
-- 
"Everybody should pay taxes with a smile"
I tried, but they want money.

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Thread

Move a div with mouse "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-07-21 13:26 +0200
  Re: Move a div with mouse Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-07-24 20:36 +0200
    Re: Move a div with mouse "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-07-24 21:58 +0200
      Re: Move a div with mouse Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-07-25 14:07 +0200
        Re: Move a div with mouse "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-07-25 19:47 +0200
          Re: Move a div with mouse Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-07-25 20:54 +0200
            Re: Move a div with mouse "danca (Daniele Campagna)" <cyberdanny@tiscalinet.it> - 2015-07-26 12:54 +0200
              Re: Move a div with mouse Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-07-26 13:36 +0200

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