There's a brief discussion of the cross-origin case in the ""ProgressEvents for Images" WhatWG thread: http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2012-January/034362.htm l and the WebKit bug about this proposed feature: https://bugs.webkit.org/show_bug.cgi?id=76102
For cross-site images for which crossOrigin is not set, we'd proposed "normalizing" the loaded and size ProgressEvent attributes: ProgressEvents for cross-origin images should not reveal the actual resource size per http://www.w3.org/TR/progress-events/#security-considerations. This could be avoided by dispatching ProgressEvents with lengthComputable=false (and loaded=0, total=0) for cross-origin images. Alternatively we could dispatch a subclass of ProgressEvent with normalized total and loaded attributes. A normalized image ProgressEvent wouldn't expose the actual size of the resource being downloaded but it would still enable developers to observe relative progress. Normalization would set total to a constant like 1000, and loaded to a relatively correct value. The motivation for providing progress events in the cross origin case is applicaitons like image galleries, that just display a list of image URLs. Displaying (possibly "normalized") download progress for images that will be displayed seems desirable. - Hans On 1/23/12 3:42 PM, "Charles Pritchard" <[email protected]> wrote: >On 1/23/12 2:55 PM, Dean Jackson wrote: >> On 17/01/2012, at 10:41 AM, Bear Travis wrote: >> >>> <img id="image" src="sample.jpg" >>> onloadstart="showProgressBar()" >>> onprogress="updateProgressBar(event)" >>> onloadend="hideProgressBar()"/> >>> >>> Developers have taken various tacks to enable progress reporting, for >>>example >>> in some cases XHR can be used to download image files. Max Vujovic >>>just >>> published a blog about the practicalities of doing so: >>> >>>http://blogs.adobe.com/openweb/2012/01/13/html5-image-progress-events/. >>> We >>> think it would be preferable to provide support for image progress >>>events >>> directly. >> I think this would be extremely useful. It would require a proposal to >> W3C or WHATWG though. > >Seems like this would need to follow CORS. >Even disclosing the file size is going too far for cross-domain without >CORS. > >-Charles >_______________________________________________ >webkit-dev mailing list >[email protected] >http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev _______________________________________________ webkit-dev mailing list [email protected] http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
