Boris Zbarsky <[email protected]> skreiv Wed, 02 May 2012 20:10:24 +0200
With my used-to-maintain-a-rich-text-component hat on, I would have
preferred a property to an event as an author.
Ah, nice. In that case, my vote is certainly for a mechanism like that!
I suggest spec'ing something like
navigator.UI.copyEnabled
navigator.UI.cutEnabled
navigator.UI.pasteEnabled
to be writeable boolean properties. Before opening a relevant menu, the
implementation can check if a script has set these properties and enable
or disable/hide commands accordingly.
The only use case this doesn't handle is to conditionally enable browser
UI depending on what format(s) are available on the clipboard. A web app
author might want 'paste' enabled if there is plain text on the clipboard,
but not if there is RTF text or an image - or vice versa, depending on the
app's nature and requirements. This is the only good use case for
beforepaste events I can think of (given, of course, that we allow the
listener to check what formats are available).
I see no use cases for beforecut and beforecopy that are not (better)
handled with properties.
Extending oncontextmenu to allow disabling/hiding menu entries was
suggested elsewhere in this thread. While that idea may have merit for
other use cases, opening the "Edit" menu will not fire oncontextmenu
AFAIK, and neither does an oncontextmenu listener typically have access to
information regarding what formats are on the clipboard.
Hence, my current thinking is that it might be best to spec beforepaste
*only*. If I do so, I'd prefer not doing magicish things with
event.preventDefault() to disable/enable browser UI. I think it would be
easier for authors to write something like
window.addEventListener('beforepaste', function(event){
if(event.clipboardData.types.indexOf('text/plain')>-1){
navigator.UI.pasteEnabled=true;
}else{
navigator.UI.pasteEnabled=false;
}
});
Any criticism of this way forward is welcome. (For example, would authors
expect *Enabled properties to be sync'ed by the implementation and show
the actual state of the UI, rather than being set from the script? Would
methods be better - navigator.UI.setCopyEnabled()?)
--
Hallvord R. M. Steen
Core tester, Opera Software
