Adding telephone number links using HTML is easy. It’s similar to calling e-mail addresses using the mailto: syntax. The last standard that includes the syntax I could find it RFC 3966, which is still valid.I recommend using telephone number links on mobile phones only and not making links for desktop or laptop devices. The reason being is that the purpose of telephone links is that a visitor can click on the link to make the call automatically, instead of entering the numbers on the phone. Due to this, it is not needed on desktop or laptops because clicking the link will not do anything as it’s not mobile phone connected. However, with this being said, I’ll show you the callto: URI for Skype.

To only show telephone links on mobile devices, try using a lightweight mobile detection class. For PHP I would recommend Mobile Detect.

The HTML

<a href="tel:+1-212-555-0101">+1-212-555-0101</a>

Here, you’ll notice the HTML markup is:

<a href="tel:{PHONE NUMBER}">{TEXT}</a>

Where {PHONE NUMBER} is the phone number to call and {TEXT} is the link text that visitor will see. You can change the {TEXT} to whatever you want..

Skype

To open Skype using a link, we’ll use callto: attribute instead of tel:

<a href="callto:+1-212-555-0101">+1-212-555-0101</a>