I need a script to make phonecall from a webpage (I have a valid SIP account)

I need a simpe script to make phone calls from a webpage. It will only be calling one number, so on the page I only need a green phone icon to start the call and a red phone icon to hang up again.

Here is some info I found:
https://sipjs.com/guides/simple/
https://jsfiddle.net/OnSIP/xv00uLur/

It needs to run on my shared hosting, so it's not possible to install additional software.