How can I Javascript a phone call from within Unity?

Hi,
I’m creating a simple app that will allow you to call a specific phone number on the iPhone when you touch its icon. I saw only one answer here but that was in C#. I am wondering if anyone knows the lines of code in Javascript that will allow me to do that.
Thanks so much!!!
Tom

Have you tried

Application.OpenURL( "tel://5555551212" );

?