How to add a Print Button to a modal

Scripting
1

I would like to add a print button to my modal which collates some data.

<button onclick="myFunction()">Print this page</button>

<script>
function myFunction() {
    window.print();
}
</script>
2

OK - got it

<input type="button" 
  onClick="window.print()" 
  value="Print This Page"/>