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Re: firstChild Problem

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On 10/10/12 13:20, Mel Smith wrote:

> // Here is the line that results in the error:
>
> srchtxt.firstChild.nodeValue = "Searching ...";

As your HTML mark-up illustrates, there is no `Text` node
with which one could work.

`<span></span>` will create an `HTMLSpanElement` in the document
tree with no child nodes.

> // Yet if I intentionally place a 'searching ...' string
> // in the<span>  on the original page, it works correctly, and if I then
> // set the nodeValue later to ""  (i.e., empty string), and re-enter my
> function,
> // there is no error ?

Yes, as the text added between the start and end tags denotes a
`Text` node that will be created as a child node of the
`HTMLSpanElement`. Thus, it is available to be scripted.

Once the node has been created in the document tree, it needs to
be removed in order to discard it--and even then, references inside
of scripts can still access it, so the references need to be cleared. 
Emptying its `nodeValue` property will not delete it: the node
still exists in the document tree.

Using intial text as you have done is a good idea, as it provides
an initial state for the client before any scripting is performed.
If JavaScript is disabled or the corresponding script does not
execute, the initial state will be presented.

-- 
`The theologian Meric Casaubon argued--in his 1668 book, *Of Credulity
and Incredulity*--that witches must exist because, after all, everyone
believes in them. Anything that a large number of people believe must
be true'--Carl Sagan--*The Demon-Haunted World*.

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Thread

firstChild Problem "Mel Smith" <med_cutout_syntel@aol.com> - 2012-10-10 11:20 -0600
  Re: firstChild Problem -- Correction "Mel Smith" <med_cutout_syntel@aol.com> - 2012-10-10 11:35 -0600
    Re: firstChild Problem -- Correction "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2012-10-10 20:42 +0300
  Re: firstChild Problem Denis McMahon <denismfmcmahon@gmail.com> - 2012-10-10 17:40 +0000
  Re: firstChild Problem Matt McDonald <matt@fortybelow.ca> - 2012-10-10 13:56 -0400
    Re: firstChild Problem "Mel Smith" <med_cutout_syntel@aol.com> - 2012-10-10 12:13 -0600

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