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Re: Change textarea readonly state

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Tom de Neef wrote:

> "Jukka K. Korpela" <jkorpela@cs.tut.fi> schreef:
>> But to save comp.lang.javascript from a confusing thread about a simple
>> matter,

I strongly suggest you heed that old wisdom, "Cobbler, stick to thy last.", 
and do not try to force an off-topic discussion (in matters obviously beyond 
your competence).

>> here's what you really wanted to ask, and the correct answer:

No.

>> Q: In JavaScript, how can I make a readonly field (one with the readonly
>> attribute) writeable?
>>
>> A: You need to remove the attribute. Changing its value won't help, since
>> its the very presence of the readonly attribute, not its value, that
>> matters. Example:
>>
>> <textarea id="ta" name=ta readonly rows="5" cols="5">Hello</textarea>
>> <input type=button value="Allow write" onclick=
>>   "document.getElementById('ta').removeAttribute('readonly')">

Of course, for various good reasons there should not be newline after the 
`='.

> Very good. The ability to interpret an unclear question is worth more than
> the ability to answer the question. And you did both.

It is _not_ necessary to remove the attribute and risk calling the error-
prone removeAttribute() method here.  The element object has a `readOnly' 
attribute *property*:

  <input type=button value="Allow write"
         onclick="document.getElementById('ta').readOnly = false">

<http://www.w3.org/TR/DOM-Level-2-HTML/html.html#ID-24874179>

That said, it is usually a bad idea to set the `readonly' *attribute* in the 
first place because it can only be reset with client-side DOM scripting or 
by a round trip to the server.

You also want to consider using the `forms' and `elements' collections 
instead of making excessive use of document.getElementById().  The least you 
should do is to cache the return value of the latter.


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PointedEars
-- 
When all you know is jQuery, every problem looks $(olvable).

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Re: Change textarea readonly state Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-06-04 14:31 +0200

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