This bookmarklet calls the phone number in the next element clicked. If a phone number does not exist or is not valid, the user is then prompted to enter a valid phone number. This continues until the user enters a valid phone number, or cancels a prompt.
To install the bookmarklet, type this into your browser's address bar (note the javascript:
part):
javascript:var%20script=document.createElement('script');script.src="https://cdn.rawgit.com/penne12/246dc4ca0d4db595fcfb07fd441ab513/raw/e2d6e480556d54f305c1619b177568dc488fc376/install-bookmarklet.js";script.type="text/javascript";document.body.appendChild(script);