Can you detect whether a device has phone capabilities (e.g. it can make voice calls/SMS) with JavaScript?

Question

I havent seen an obvious way to see that sms: and tel: links get special treatment.

Update: @janogosteve below has confirmed there is currently no reliable feature detect. This looks undetectable.

Here’s a comprehensive way to check this feature detect. (Read jangosteve comment below!)

make a test page with two of those links and a regular http link
grab the elements and then traverse all their properties, copy it all over to an object..
also getComputedStyle info for a bunch of details on them and throw that into an object as well
JSON.stringify( that stuff so you can deal with it later on)

Do the above on an iOS device and in desktop Safari/Chrome

Then JSON.parse them back into objects… and use https://github.com/NV/objectDiff.js to see if you can spot any differences at all.