[whatwg] Request for new DOM property textarea.selectionText
Ian Hickson
ian at hixie.ch
Mon Apr 30 23:26:40 PDT 2012
On Mon, 30 Apr 2012, Ryosuke Niwa wrote:
> >
> > Seems like it'd be better just to have UAs optimise their JS string
> > implementations so that it can just be backed by the same thing as the
> > DOM or the control's editor. (I believe Mozilla may in fact already do
> > that.)
>
> In theory, this is possible. But any sort of proxy, etc... that lazily
> obtain the value (e.g. delaying it until substr, etc... is called) is
> hard to implement in practice because we need to serialize text before
> DOM is modified. e.g.
>
> 1 var inputValue = input.value;
> 2 var textUsed = input.value.substr(5, 10);
>
> In the above example, inputValue could be a proxy object. However, in
> the example below:
>
> 1 var inputValue = input.value;
> 2 input.value = 'bar';
> 3 var textUsed = input.value.substr(5, 10);
>
> we need to serialize the string immediately before the statement in the
> line 2 is evaluated.
That's just copy-on-write. It's hardly rocket science. :-P
--
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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