Silverlight preempted by Seajax in secondary browsers even when SL3 installed. But why?

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  • Updated 11 years ago
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Well the title says it all and I've been meaning to ask this almost since the first day that I tried Seadragon.com out and praised the automatic stepping up to Silverlight when available of the Seadragon 'combo' viewer.

On both Windows and OSX browsers that aren't explicitly on the 'Silverlight supported browsers' list get sniffed and served the Seajax version of the Seadragon.com viewer even if Silverlight is installed and up to date on the machine.

Example: In Opera 10, Safari 4, and Google Chrome Silverlight apps work, even though they aren't on the Silverlight guest list. In my experience the Silverlight Photosynth viewer may as well be the Acid 3 test for Silverlight. On my computers all three browsers mentioned at the beginning of this paragraph run that viewer. I will grant you that for whatever reason Opera gets the scrollwheel directions backwards with the Photosynth viewer, but shouldn't I at least be able to try the Seadragon embeds in Silverlight in these browsers?

I suppose all I would need to do is mask my useragentstring to see whether this is the preemption on your part that I think it is, but it's easier to come ask your team what's up, so here I am. Any particular reason why I'm passed the Seajax control when the Silverlight control should theoretically work?
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Nathanael Lawrence

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Posted 11 years ago

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Photo of Aseem Kishore

Aseem Kishore, Former Employee

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Official Response
Hey Nathanael,

We do currently use the official Silverlight.supportedUserAgent.js helper library to determine if the browser is officially supported by Silverlight.

The reason for this is that we did come across bugs in Chrome (mouse wheel jitter) and Opera (unreliable button image loading) during development, and it eventually seemed better to go by the "officially supported" whitelist than our own ad hoc blacklist.

The bugs weren't major, and there are probably ways we can work around them, but we haven't had the resources to investigate them much more. Long-term, we do indeed want to use Silverlight everywhere if the user has it installed; we're just not there yet. =)

Aseem