how to code NodeList.getElementsByTagName

Dormilich

8,658 Expert Mod 8TB

I’m trying to do the following

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document.getElementsByTagName("sup").getElementsByTagName("a");

currently I have this because I somehow need to return a combined result NodeList

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 // can’t prototype into NodeList because of Firefox

if (!Object.getElementsByTagName && Object.length)

{

    Object.prototype.getElementsByTagName = function(name)

    {

        // the only idea I got

        var div = document.createElement("div");

        for (var i=0, len=this.length >>> 0; i<len; i++)

        {

            if (i in this)

            {

                div.appendChild(this[i]); // line 92

            }

        }

        return div.getElementsByTagName(name);    

    }

}

but when running the code (FF 3.5.2) I get the following Exception:

uncaught exception: [Exception... "Component returned failure code: 0x80004003 (NS_ERROR_INVALID_POINTER)" nsresult: "0x80004003 (NS_ERROR_INVALID_POINTER)" location: "JS frame :: http://localhost/phileasson.xhtml#n1-1 :: anonymous :: line 92" data: no]

there are some <sup> before that, which do work. by checking the created div I found that the mentioned node has been already copied …

can anyone help me in that matter?

HTML sample code

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 <h4>15<sup>th</sup> – 24<sup>th</sup> Hesinde<sup><a href="#n1-3">3</a></sup></h4>
 

Sep 8 '09 #1

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✓ answered by Dormilich

ok, now that we figured out we can’t create NodeLists by ourselves, I’ll return to the original idea of putting the relevant elements to a common (new) parent and use that to apply getElementsByTagName(). I basicly need some sort of pointers, because the original plan didn’t work as expected, I can’t use cloned nodes and moving the nodes between document and ‘parent’ is very inconvenient.

any ideas in this direction?

5740

Dormilich

8,658

Expert Mod 8TB

I can prevent the Exception by

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div.appendChild(this[i].cloneNode(true));

but that’s not returning the NodeList I need later …

Sep 8 '09 #2

RamananKalirajan

608

512MB

Hi Dormilich,
Do u want to get the anchor object inside the <sup>? I tried out this one...

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function callJS(){

        var subObj = document.getElementsByTagName('sup');

        for(i=0;i<subObj.length;i++)

        {

            try

            {

                var aObj = subObj[i].getElementsByTagName('a');

                if(aObj.length>0)

                {

                    alert("I got the Object at the Index "+i);

                }

            }

            catch(e)

            {}

        }

    }

Thanks and Regards
Ramanan Kalirajan

Sep 8 '09 #3

Dormilich

8,658

Expert Mod 8TB

@RamananKalirajan
yes, I want to get those anchors (which is not a problem as is), but I need them returned as one list (which is the problem here). an alert is of no use here :(

maybe it also works when returning an Array (though that’s not the same) …

Sep 8 '09 #4

Frinavale

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Expert Mod 8TB

Sorry, but what's the difference between "one list" and an array?

Sep 8 '09 #5

Dormilich

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Expert Mod 8TB

RamananKalirajan’s code doesn’t have a return value (aka one list)

getElementsByTagName() usually returns a NodeList. if I prototype getElementsByTagName into the NodeList interface I’d like it to return a NodeList too (because that’s what you’d expect). if everything fails it could also return an array…

Sep 8 '09 #6

Frinavale

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Expert Mod 8TB

Could the NamedNodeMap help you at all??

Sep 8 '09 #7

Frinavale

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Expert Mod 8TB

I think the NodeList is immutable (see this article...)...

Sep 8 '09 #8

Dormilich

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Expert Mod 8TB

that’s also the impression I got…

Sep 8 '09 #9

Frinavale

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Expert Mod 8TB

I tried it...but it just wont work.
I don't think you can join NodeLists together.
Best I could do was create an array of nodes

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<html>

<head>

</head>

<body>

<input type="text" id="text1" name="text1" />

<input type="text" id="text2" name="text2" />

<input type="text" id="text3" name="text3" />
 
<select id="select1" name="select1"> 

<option>1</option>

<option>2</option>

</select>

<select id="select2" name="select2">

<option>1</option>

<option>2</option>

</select>
 
<script type="text/javascript">
 
var inputs = document.getElementsByTagName('input');

var selects = document.getElementsByTagName('select');
 
var all = new Array(inputs.length + selects.length);

var index = 0;

for (i = 0; i < inputs.length; i++)

    all[index++] = inputs[i];

for (i = 0; i < selects.length; i++)

    all[index++] = selects[i];
 
</script>
 
</body>

</html>

Sorry...maybe someone else knows more :)
I'm pretty new to JavaScript.

Sep 8 '09 #10

Dormilich

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Expert Mod 8TB

@Frinavale
for being new you’re quite good :)

Sep 8 '09 #11

Frinavale

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Expert Mod 8TB

Haha thanks Dorm :)

I sometimes think that JavaScript is going to make my head explode. I think that over half of my problems these days has something to do with JavaScript (and the messed up idea of what Microsoft thinks Ajax should be).

Sep 8 '09 #12

Dormilich

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Expert Mod 8TB

@Frinavale
that’s the point, if everyone (and I mean everyone) would stick to the specs, life would be a lot easier.

Sep 8 '09 #13

Frinavale

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Expert Mod 8TB

@Dormilich
Sometimes it's breaking the specs that advances technology though. So even though I would love for MS to follow the rules (because it would make my life a LOT easier), I think that we would be set back a lot by enforcing the rules on everyone...

How else are we supposed to know whether or not to change the specs (in order to advance technology) unless we try the bad with the good?

Sep 8 '09 #14

Dormilich

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Expert Mod 8TB

@Frinavale
that’s part of the development cycle…

Sep 8 '09 #15

Dormilich

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Expert Mod 8TB

Sep 9 '09 #16

how to code NodeList.getElementsByTagName

✓ answered by Dormilich

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