If/else help needed please *solved*

I've tried to do this myself, but I'm missing something as it doesn't work! Could someone correct me please

Basically, if the VatValue.3 field says 'Exempt', the aVATRate.3 field should say 0, but if the field shows a percentage value (eg 20%), them it should show the value divided by 100.

if (this.getField("VatValue.3").value == "Exempt") {
event.value = 0;
}
else {
event.value = .value/ 100.0;
}