Open Web Platform Weekly Summary – 2012-03-12 – 2012-03-18

The Open Web Platform weekly summary with HTML, ARIA, ITS, Webapps, DOM and Canvas. See also Anne’s blog post about Path API for SVG and Canvas.


HTML 4 and HTML5

There is a thread on proposing to update HTML 4 to inform readers about HTML5 being developed. Not everyone agrees.

HTML5 microdata and ITS

Jirka Kosek is working on a mapping of ITS vocabulary to HTML5 and microdata. ITS is a way to express that a content should not be translated and keep as-is. It also gives the possibility to give specific instructions for localization. A discussion started on what would be the most appropriate way of doing it.

ARIA role in HTML5

What does that mean for implementations when there is a redundancy of markup with the same semantics such as in the ARIA case for button.

<button role="button" aria-pressed="true">
<button aria-pressed="true">

Implementations seems to behave differently on these two examples of code.

startTime for videos

When using the video API, startOffsetTime seems to be misunderstood by people and then barely implemented, Odin Hørthe Omdal (Opera Software) is proposing to have a startTime which is a not normalized to UTC value. This would enable to do things like

startTime + currentTime

to get the actual timestamp that the stream is at, at that point.

Canvas Elliptical Arcs

You could already draw circular arcs with canvas. A new property to draw Elliptical arcs has been added to Canvas. We can now easily draw spaceships orbits.


Meeting in the Silicon Valley

The Webapps Working Group is meeting on May 1-2, 2012 in Mountain View, USA. The agenda is being worked on.

Undo Manager

Ryosuke Niwa (webkit) pointed out that there was an issue in the Undo Manager in nested transactions and execCommand on

<div id="um1" undoscope><span id="um2" undoscope></span></div>
um1.undoManager.transact({ // transaction 1
executeAutomatic: function() {
um2.undoManager.transact({ // transaction 2
  executeAutomatic: function () {
    um2.appendChild(document.createTextNode('In um2')); // statement 1
    um1.appendChild(document.createTextNode('In um1')); // statement 2


Ojan Vafai (Chromium) proposed to deprecate NodeList.

Dynamic NodeLists have a significant memory and performance cost. Static NodeLists are basically just under-powered arrays. We should just return Node arrays from any new APIs that return a list of Nodes.

WebMessaging and Workers Last Call

WebMessaging allows you to pass messages in between window contexts in a browser. The deadline for commenting on WebMessaging Last Call is April 3, 2012. There is also a last call for the Workers specification.


String encoding and decoding API

Jonas Sicking (Mozilla) mentioned the need for an API for encoding/decoding ArrayBuffers into text. But it was mentioned that maybe a better solution was to build on the work of Joshua Bell, a string encoding and decoding API, separable from the core typed array API. The discussion is going on.


New SVG charter draft

A new SVG charter draft has been submitted for review by the public. The chairs will be Erik Dahlström (Opera), Cameron McCormack (Mozilla). It includes the definition of a markup syntax, compatible with XML and HTML5 parsing, an API compatible with the DOM, and style properties.


Christian Schmidt proposed to have a new HTTP header, Window-Target:, to cope with the time when we do not know yet if the link should be opened in _blank or _self at the moment the user clicks on the link.

This column is written by Karl Dubost, working in the Developer Relations team at Opera Software.