Imagemapster print selected

Question

Im trying to print all selected areas when button is pushed, but cannot get it to work. Im using this example to learning.

https://github.com/jamietre/ImageMapster/blob/main/examples/staticstate.html

What i have done:

function printChecked() {
        var selectedPrint = $image.mapster('get');
         document.getElementById("print").innerHTML = selectedPrint;
        }

Inside of body:

<p><input type="button" onclick="printChecked()" value="Print Selected Items" /></p>
        <p id="print"></p>