On Wed, Jul 6, 2011 at 1:27 AM, Dave Raggett <d...@w3.org> wrote: > On 04/07/11 21:43, Olli Pettay wrote: >> >> In the easiest case when the script cares about only one specific >> attribute: >> element.**addAttributeChangeListener( >> { >> prevVal: element.getAttribute("foo"), >> handleMutation: function(node, changeTarget) { >> if (node == changeTarget) { >> // do something with this.prevVal >> ... >> this.prevVal = element.getAttribute("foo"); >> } >> } >> }); >> > > How does that scale to the case where you set the observer on the document > or on a div element acting as a contained for content editable content? If > I am not mistaken you would have to keep a copy of the document, or of that > div element respectively, and keep it in sync with all of the mutations, > which sounds like a major performance hit, and something you don't need to > incur with the current DOM mutation events.
We should probably include the old value optionally. - Ryosuke