refresh contents of text field based on combo box

Hi

I have a text field "UNIT PRICE" - it is formatted to display a different currency based on the currency selected in combo box "Currency".

When a value is already entered in UNIT PRICE and the user realises they picked the wrong currency and changes it, the format of UNIT PRICE does not change (eg if £ was selected, then $ picked instead - the format remains £XX.XX...)

if (this.getField("Currency").value == "USD $" ){ 
AFNumber_Format(2, 0, 0, 0,"$", true)};
 
if (this.getField("Currency").value == "GBP £" ){ 
AFNumber_Format(2, 0, 0, 0,"£", true)};
 
if (this.getField("Currency").value == "EUR €" ){ 
AFNumber_Format(2, 0, 0, 0,"€", true)};
 
 
 
if(event.value == "$0.00") event.value = '';
if(event.value == "£0.00") event.value = '';
if(event.value == "€0.00") event.value = '';

Thanks!

PS I'm quite sure this is far from the simplest way to have written this code, forgive my newbie-ness