- From: Simon Pieters <simonp@opera.com>
- Date: Fri, 11 May 2012 20:52:43 +0200
- To: "whatwg@whatwg.org" <whatwg@whatwg.org>
There seem to be two proposals for what syntax to use for the responsive images use case: several elements vs. an attribute. I think an attribute is simpler to implement and thus likely to result in fewer bugs in browsers, which in turn benefits Web developers. With <img src="..." srcset="...">, in the parser case, all the information is available when the tag has been parsed. Excellent! In the scripted case, we need to "await a stable state" when the src or srcset attributes are changed (because the same script might also change the other), and then process the attributes again. The spec already does this for src="" because of the crossorigin="" attribute, so it's basically a solved problem already for <img> in the spec. With <picture><img src="..."><source ...>...</picture>, in the parser case, the browser can't know it has all the information is not available until the picture element has been popped off the stack (since there might be futher <source> elements), which necessarily delays fetching the image. Moreover, scripts might have changed things before then, because scripts can run between the time that the "picture" element is added to the document and the time it is popped off the stack, which is a potential source for bugs. In the scripted case, we need to listen for changes to img elements' parents, changes to img element's attributes, changes to source elements' parents, and changes to source elements' attributes, and "await a stable state" and then process the picture element's img and source elements' attributes (for both the old and new picture element, if you moved an element between two picture elements), which is more complex than the attribute case. -- Simon Pieters Opera Software
Received on Friday, 11 May 2012 18:53:27 UTC