Prev: Internet Explorer Compatibility Views
Next: FAQ Topic - Why does simple decimal arithmetic give strange results? (2010-05-28)
From: Matt Kruse on 27 May 2010 10:26
On May 27, 8:18 am, Martin Honnen <mahotr...(a)yahoo.de> wrote:
> Matt Kruse wrote:
> > What is the best way to determine if #x is a child of the inserted
> > element?
> Firefox also supports XPath over HTML DOMs so you could also try to
> solve that with XPath e.g.
>    element.ownerDocument.evaluate('descendant-or-self::*[@id = "' +
> yourId + '"]', element, null, 9, null).singleNodeValue !== null

Good idea, I went ahead and tested these three:

function containsId1(el,id) {
return (el.ownerDocument.evaluate('descendant-or-self::*[@id = "' +id
+ '"]', el, null, 9, null).singleNodeValue !== null);
}
function containsId2(el,id) {
return (el.querySelectorAll('#'+id).length==1);
}
function containsId3(el,id) {
var o = document.getElementById(id);
if (o) {
if (id===o.id) { return true; }
while (o=o.parentNode) {
if (id===o.id) { return true; }
}
}
return false;
}

It turns out that the XPath approach is about 100ms slower over 5,000
iterations of a simple test case (insignificant), and the other two
are practically equal. So I guess there is no reason not to use the
last approach, which is the most backwards-compatible.

Matt Kruse
From: SAM on 27 May 2010 11:48
Le 5/27/10 3:07 PM, Matt Kruse a �crit :
> Using a document listener on DOMNodeInserted, I'm trying to determine
> if an element with id="x" was inserted.

alert(document.getElementById('x'))

alert(typeof document.getElementById('x') != 'undefined')

> So either the event.target.id=="x"
> or a child element of the one inserted
> has .id=="x".

??? as you can have only ONE element of same id in a html body
why do you search more than this 'x' ?


> What is the best way to determine if #x is a child of the inserted
> element?

?? how does-it inserted ?
I mean the container or the element of id 'x'


> Currently I'm doing:
> if ( element.querySelectorAll("#x").length==1 )

I don't know what that element.querySelectorAll is.


> But that limits my browser compatibility. I'd like to support Firefox
> < 3.5, which lacks querySelectorAll.

If you search an id use gEBY (see above)



If there is more than one element with same id
correct in first your page or the appli creating it.

--
sm
From: Matt Kruse on 27 May 2010 13:31
On May 27, 9:26 am, Matt Kruse <m...(a)thekrusefamily.com> wrote:
> function containsId3(el,id) {
>         var o = document.getElementById(id);
>         if (o) {
>                 if (id===o.id) { return true; }
>                 while (o=o.parentNode) {
>                         if (id===o.id) { return true; }
>                 }
>         }
>         return false;
> }

Oops, posted the version with obviously logical snafu. Fixed:

function containsId3(el,id) {
var o = document.getElementById(id);
if (o) {
do {
if (o==el) { return true; }
} while (o=o.parentNode);
}
return false;
}

Matt Kruse
From: Garrett Smith on 27 May 2010 13:52
On 5/27/2010 7:10 AM, Thomas 'PointedEars' Lahn wrote:
> Matt Kruse wrote:
>
>> Thomas 'PointedEars' Lahn wrote:
>>> Matt Kruse wrote:
>>>> What is the best way to determine if #x is a child of the inserted
>>>> element?
>>> Determine if #x's parent is the inserted element (`parentNode' property).
>>
>> I thought of this too, obviously, but it has the drawbacks of:
>> 1. You may have to look through the parentNode chain all the way up to
>> the root document
>

No, to determine if #x is a child of the inserted element, the simplest
approach is to compare the inserted element to x's parentNode.

To determine if #x is a *descendant* of the inserted element is a
different task. It is not a difficult one; and many recent browsers
supply functionality

You wrote that you are using a DOMNodeInserted mutation event. Perhaps
that is not the best choice here.

What are you trying to do?

From: Thomas 'PointedEars' Lahn on 27 May 2010 14:00
Garrett Smith wrote:

> On 5/27/2010 7:10 AM, Thomas 'PointedEars' Lahn wrote:
>> Matt Kruse wrote:
>>> Thomas 'PointedEars' Lahn wrote:
>>>> Matt Kruse wrote:
>>>>> What is the best way to determine if #x is a child of the inserted
>>>>> element?
>>>> Determine if #x's parent is the inserted element (`parentNode'
>>>> property).
>>>
>>> I thought of this too, obviously, but it has the drawbacks of:
>>> 1. You may have to look through the parentNode chain all the way up to
>>> the root document
>
> No, to determine if #x is a child of the inserted element, the simplest
> approach is to compare the inserted element to x's parentNode.
> [...]
> What are you trying to do?

Will you *please* learn to post.


PointedEars
--
Danny Goodman's books are out of date and teach practices that are
positively harmful for cross-browser scripting.
-- Richard Cornford, cljs, <cife6q$253$1$8300dec7(a)news.demon.co.uk> (2004)
First  |  Prev  |  Next  |  Last
Pages: 1 2 3 4
Prev: Internet Explorer Compatibility Views
Next: FAQ Topic - Why does simple decimal arithmetic give strange results? (2010-05-28)