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Message-ID: <3007137.SPkdTlGXAF@PointedEars.de>
From: Thomas 'PointedEars' Lahn <PointedEars@web.de>
Reply-To: Thomas 'PointedEars' Lahn <cljs@PointedEars.de>
Organization: PointedEars Software (PES)
Date: Wed, 02 Nov 2011 21:25:44 +0100
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Subject: Re: Second window
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Tom de Neef wrote:

> "Thomas 'PointedEars' Lahn" <PointedEars@web.de> wrote:
>> You will have to use the same window name so that window.open() returns a
>> reference to the Window instance.
>>
>> As it is, your approach is flawed.  document.write() will always
>> overwrite the content if the document has been loaded, but it will not
>> automatically close the output stream (you need document.close() for
>> that). window.open() will always replace what you might have written with
>> document.write() before.
>>
>> You should check if `secondWindow' refers to a Window (`secondWindow
>> converts to true) that is not closed (`closed' property is false), and
>> only call window.open() if neither is the case.  Feature-test the focus()
>> method before you call it then, and catch any exceptions the call might
>> still throw.
> 
> Thank you. But...
> 
> function load2ndWindow(query) {
>   if (secondWindow && !secondWindow.closed) secondWindow.clear();
>   secondWindow = window.open(query,"Support", ...);
> }
> 
> Loading the query results from the server may take some time. I want to
> avoid the situation where the user sees obsolete previous data in the
> support window.

I did not think of that.  Your approach is sound then if you close the 
output stream.  However, you might want to write a complete HTML document 
then, as I am not sure that all browsers would automatically wrap the text 
in one.  And never have a textual empty document; this is not user-friendly.  
But see below.

> There are three situations to consider:
> […]
> c) a support window exists but (due to reloading of the main page) the
> global secondWindow has value null. What happens now is: the support
> window gets the focus and shows obsolete data while waiting for the new
> data to arrive from the server.
> 
> This last situation I want to avoid. Is there a way to associate the
> variable secondWindow with an existing window, other than via window.open?

No, but there is another possibility: You can focus an existing popup window 
only when its content has been loaded, preferably in the `load' listener of 
the new support document's body (`onload' attribute value).


HTH

PointedEars
-- 
Anyone who slaps a 'this page is best viewed with Browser X' label on
a Web page appears to be yearning for the bad old days, before the Web,
when you had very little chance of reading a document written on another
computer, another word processor, or another network. -- Tim Berners-Lee