Java Script Error - Please Help

Hi,

I have written the code below to take the values of two Text fields, put them together and remove spaces, but it comes up with an error;

FRN 123456

Postcode E1 1XX

Would equal BranchID 123456E11XX and be populated into another field,

function updatebranchid()

{

// Gets Values from the FRN Field and Postcode

var FRN = Xrm.Page.getAttribute("liss_frnno").getValue();

var Postcode = Xrm.Page.getAttribute("address1_postalcode").getValue();

// Combines the FRN and Postcode

Var FRNPostcode = FRN + Postcode

// Removes the Spaces

Var BranchID = FRNPostcode.replace(" ","")

// Populates LVBranchID

Xrm.Page.getAttribute("liss_lvbranchid").setValue(BranchID);

}