firstchild

[Matej]

Hello gentlemen

<table id="outside">    <tr><td id="t1">one</td></tr>    <tr><td id="t2">two</td></tr></table>

var t2 = document.getElementById("t2");alert(t2.firstChild.nodeValue)

Why does this alert "two" (value of t2) while t2 does not have childrens?

 

but when i use

var t2 = document.getElementById("outside");alert(t2.firstChild.nodeValue)

it does not alert anything

Also can someone explain to me when do i use "true" and when do i use "false" in element.addEventListener()?

 

 

Thanks for answering and have a nice day

Edited June 3, 2014 by Matej

[dsonesuk]

Because

<tr><td id="t2">two</td></tr>

 

has no line breaks or spacing which would register as text node, it shows 'two', where as

 

<table id="outside"> <tr><td id="t1">one</td></tr> <tr><td id="t2">two</td></tr></table>

 

does have line breaks and probably space it would register that as a node and show it as a blank, change '.nodeValue' to '.nodeName' and see what happens, also JavaScript created tables, generally create tbody elements etc, by default so you may see these and not what you expected.

[Matej]

it does the same thing when i add spacing and breaks

 

also it shows #text via nodeName (on both of the cases)

Edited June 3, 2014 by Matej

[dsonesuk]

        <table id="outside"><!-- line break or space = nodename #text and show as blank with nodevalue (may show as tbody)-->            <tr><td id="t1">one</td></tr> <!--No line break or space but text of 'one' = nodename #text and show as 'one' with nodevalue -->            <tr>                <td id="t2"><!-- line break or space = nodename #text and show as blank with nodevalue -->                    two                </td>            </tr>        </table>

[Matej]

Thanks so basicly , every break counts as node here right?

[dsonesuk]

yep! but it is i think you will find it is browser dependant, just try it in different browsers to see if #text shows or other.

[Matej]

thanks! and what would be lastChild of <tr id="t1"><td>one</td></tr>? it shows "TD" but isnt it #text with nodeValue "one"?

[dsonesuk]

No, 'one' is first and last child of <td>, as the td is the first and last child of <tr> with id ref of 't1'

 

To show nodeValue 'one' it would have to be

 

alert(t1.childNodes[0].lastChild.nodevalue); ='one'

alert(t1.childNodes[0].lastChild.nodeName); = '#text'

 

tr -> td -> text

Edited June 4, 2014 by dsonesuk