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Re: Get inner text of HMTL element

From Cezary Tomczyk <cezary.tomczyk@gmail.com>
Newsgroups comp.lang.javascript
Subject Re: Get inner text of HMTL element
Date 2014-02-22 23:38 +0100
Organization A noiseless patient Spider
Message-ID <leb8sc$23n$5@dont-email.me> (permalink)
References (1 earlier) <5308ed02$0$9512$9b4e6d93@newsspool1.arcor-online.net> <leav3t$aa4$5@dont-email.me> <1633562.pVBMJriu5e@PointedEars.de> <leb1q1$r9i$1@dont-email.me> <1780761.mlrEmVmIzg@PointedEars.de>

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Thomas 'PointedEars' Lahn wrote:
> Cezary Tomczyk wrote:
[...]
>> function get_inner_text(elm) {
>>       var txt = '';
>>       if (elm && elm.childNodes && elm.childNodes.length > 0) {
>>           txt = elm.data || elm.textContent || elm.innerText;
>>       }
>>       return txt;
>> }
>
> Better (but unnecessarily inefficient: consider the “firstChild” property),
> but see below.

True. I've rewritten it to:

function get_inner_text(elm) {
     var txt = '';
     if (elm && elm.firstChild) {
         txt = elm.textContent || elm.innerText;
     }
     return txt;
}

There is no "elm.data". I've explained it below.

[...]
>>> What is the result of
>>>
>>>     "" || void 0 || void 0
>>>
>>> ?
>>
>> "" is converted to "false" boolean
>> void 0 is evaluated to "undefined" and then to "false" boolean
>>
>> Because all of them are converted to "false" boolean then "undefined" by
>> default is returned.
>>
>> How about that?
>
> The final operand¹ is not converted, and no operand is actually converted
> (instead of just internally for the purpose of determining shortcut
> evaluation).  And nothing is *returned*.  Otherwise you have described it
> correctly.

Right. I was thinking about default return value when function has no 
defined "return" statement. But in this case there is no function at all.

>> function get_inner_text(elm) {
>>       var txt = (elm.data || elm.textContent || elm.innerText);
>>       if (!txt) {
>>           txt = '';
>>       }
>>       return txt;
>> }
>
> Much the same could be achieved with
>
>    var text = elm.data || elm.textContent || elm.innerText || "";
>
> and it would still be wrong.

:-( There is no "elm.data".

> For a start, one wonders how you got the idea that an *element* object had a
> (built-in, standards-compliant) “data” property to yield the text content of
> the represented element.

I have no idea how it happened. I've already worked with the property 
"data", but I forgot that it apply only to TextNode object 
(http://msdn.microsoft.com/en-us/library/ie/cc304097%28v=vs.85%29.aspx).

After longer research, experimenting and reading 
(http://www.kellegous.com/j/2013/02/27/innertext-vs-textcontent/) I 
think I can build something like this:

var get_inner_text;

if (typeof document.getElementsByTagName('html')[0].textContent === 
'string') {
     get_inner_text = function(node) {
         return node.textContent;
     };
} else if (document.createTreeWalker) {

     get_inner_text = function(root) {
         var w = document.createTreeWalker(root, 4, null, false),
             result = '';
          while (w.nextNode()) {
              result += w.currentNode.data;
          }
          return result;
     };

} else {

     get_inner_text = function(node) {
         var txt = '';

         node = node.firstChild;
         while (node) {
             if (node.nodeType === 3 || node.nodeType === 4) {
                 txt += node.data;
             } else if (node.nodeType === 1){
                 txt += get_inner_text(node);
             }
             node = node.nextSibling;
         }
         return txt;
     };
}

How about that?

> _______
> ¹ Colloquially speaking; actually, we are looking at only one “||” operation
>    whose first operand is the result of another one: “a || b || c” is parsed
>    like “(a || b) || c” due to the production
>
>    | LogicalORExpression(NoIn) :
>    |   LogicalANDExpression(NoIn)
>    |   LogicalORExpression || LogicalANDExpression(NoIn)
>
>    <http://ecma-international.org/ecma-262/5.1/#sec-11.11>

Thanks.

-- 
Cezary Tomczyk
http://www.ctomczyk.pl/

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Thread

Get inner text of HMTL element Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2014-02-22 18:21 +0100
  Re: Get inner text of HMTL element Martin Honnen <mahotrash@yahoo.de> - 2014-02-22 19:31 +0100
    Re: Get inner text of HMTL element Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2014-02-22 20:51 +0100
      Re: Get inner text of HMTL element Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-22 21:11 +0100
        Re: Get inner text of HMTL element Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2014-02-22 21:37 +0100
          Re: Get inner text of HMTL element Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-22 22:05 +0100
            Re: Get inner text of HMTL element Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2014-02-22 23:38 +0100
              Re: Get inner text of HMTL element Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-23 10:43 +0100
                Re: Get inner text of HMTL element Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2014-02-23 14:50 +0100
                Re: Get inner text of HMTL element Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-23 15:48 +0100
                Re: Get inner text of HMTL element Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2014-02-24 21:01 +0100
                Re: Get inner text of HMTL element Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-24 22:34 +0100
                Re: Get inner text of HMTL element Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2014-02-27 21:41 +0100
                Re: Get inner text of HMTL element Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-27 22:32 +0100
                Re: Get inner text of HMTL element Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2014-02-28 13:44 +0100
                Re: Get inner text of HMTL element Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-28 16:54 +0100
                Re: Get inner text of HMTL element Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2014-03-04 20:51 +0100
                Re: Get inner text of HMTL element ompalompasales2@gmail.com - 2014-03-04 12:59 -0800
  Re: Get inner text of HMTL element Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-22 20:59 +0100
    Re: Get inner text of HMTL element Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2014-02-22 22:23 +0100
      Re: Get inner text of HMTL element Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-22 23:32 +0100
  Re: Get inner text of HMTL element Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-02-22 21:27 -0300
    Re: Get inner text of HMTL element "se" <se@no-one.here> - 2014-02-23 05:35 +0100
      Re: Get inner text of HMTL element Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-02-23 15:29 -0300
        Re: Get inner text of HMTL element "se" <se@no-one.here> - 2014-02-23 21:01 +0100
    Re: Get inner text of HMTL element Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2014-02-23 20:02 +0100
      Re: Get inner text of HMTL element Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-23 21:55 +0100
        Re: Get inner text of HMTL element Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2014-02-24 08:37 +0100
          Re: Get inner text of HMTL element Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-24 12:30 +0100
            Re: Get inner text of HMTL element Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-02-24 15:09 -0300
              Re: Get inner text of HMTL element Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-24 19:43 +0100
                Re: Get inner text of HMTL element Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-02-24 18:12 -0300
                Re: Get inner text of HMTL element Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-24 22:51 +0100
              Re: Get inner text of HMTL element Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-02-25 19:49 +0000
                Re: Get inner text of HMTL element Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-02-26 05:20 -0300
                Re: Get inner text of HMTL element "se" <se@no-one.here> - 2014-02-26 17:10 +0100
                OT - Re: Get inner text of HMTL element Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-02-26 15:48 -0300
                Re: OT - Re: Get inner text of HMTL element "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-02-26 22:43 +0100
                Re: OT - Re: Get inner text of HMTL element Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-02-27 15:00 +0000
                Re: OT - Re: Get inner text of HMTL element "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-02-28 10:50 +0100
                Re: OT - Re: Get inner text of HMTL element "se" <se@no-one.here> - 2014-02-27 10:57 +0100
                Re: Get inner text of HMTL element Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-02-27 15:46 +0000

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