How to make phone number a Click to Call on Phone?
After making various finding we come to conclusion to have following
Wrap all phone numbers in hyperlinks with the tel: schema.
Always use the international dialing format.
NIST Telephone Time-of-Day Service
<a href="tel: 1-303-499-7111"> 1 (303) 499-7111</a>
This we found on google developer page and found it working
https://developers.google.com/web/fundamentals/native-hardware/click-to-call/
If you want to detect phone browser etc following articles will be useful
http://stackoverflow.com/questions/26088523/click-to-call-html
http://stackoverflow.com/questions/1164004/how-to-mark-up-phone-numbers
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