Create a button that triggers a javascript

Dear Experts,

I need your help please.
We have HPSM 9.30.

We have integrated our HPSM with external system using webservices.

I need to create a button for specific tickets that whenever the user clicks on that button, it will call the javascript to create a new ticket in the external system.
Can you please help me how to create that button (step by step) that calls my javascript.

Thanks in advance.