A check-box is a field like any other, and therefore has a value property,
which can either be "Off" or the value set as the export value.
So if you confirm that the value of the check-box is not "Off", then you
know it's checked.
Yes, except you are accessing the value property twice.
Change the first line to:
v1 = this.getField("Check");
Perfect, thanks for your help!