Error in field calculation

I am trying to get a field to do a simple calculation and put the result in another field.  Here is what I have

Field 1 = Estimated Project Amount (estimated amount of a project)

Field 2= Fee % (Fee percentage we'll apply to that)

Field 3 = Construction Fee (the result - for instance 15% on a $1,000,000 project would result in 150,000)

In the Fee% field i have the following event in the Fee% field - On Change

function calculate()

{

 var val1 = Xrm.Page.entity.attributes.get('new_estimatedprojectamt").getValue();

 var val2 = Xrm.Page.entity.attributes.get("new_fee").getValue();

 if (val1 == null) return;

 if (val2 == null) return;

 var result = val1 * val2;

 Xrm.Page.entity.attributes.get("new_constructionfees").setValue(result);

 }

When i try to enter a number into the field i get the following error

There was a error with thie field's customized event

Field: new_fee

Event:onchange

Error:'calculate' is undefined