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Intent to Implement and Ship: HTMLImageElement's srcset attribute (DPR switching)


Yoav Weiss Sep 3, 2013 3:32 PM
Posted in group: blink-dev

Primary eng (and PM) emails

yo...@yoav.ws


Spec

http://www.w3.org/TR/html-srcset/


Summary

The `srcset` attribute enables authors to adapt image resources to the device's
display characteristics. This intent refers to the DPR switching parts (the 'x' qualifier), which have rough consensus around them.

Motivation

New device form factors and screen DPRs are added to the market on a regular basis. Serving the same image resources to all devices (which may display them in differing dimensions and at different DPRs) is wasteful, and hurts Web performance.


This feature will start resolving this problem, by enabling Web authors to specify multiple resources, with varying DPR qualities, and let the browser pick the resource that matches the device's capabilities.


Compatibility Risk

Low. 


This feature is identical to the feature that landed in WebKit recently (The CL is a port of the WebKit code). It is not yet implemented in IE or Firefox.


The feature's syntax include an inherent fallback mechanism for authors, where non-supporting browsers will simply fetch the resource specified in the `src` attribute. (resulting in a sub-optimal, but fully-functional image)


Ongoing technical constraints

None.


Link to “Intent to Implement” blink-dev discussion

There was no previous "Intent to implement", but there was a previous discussion on Blink-dev which was mostly positive.


Is this feature supported on all five Blink platforms (Windows, Mac, Linux, Chrome OS and Android)?

Yes.


OWP launch tracking bug?

http://crbug.com/284722


Row on feature dashboard?

Yes.


Requesting approval to ship?

Yes.