行 11、12、13 で次のコード構文エラーに問題があります。
// Get the field values
var DP = +getField("DESIGN_Projection").value;
var TC = +getField("ASBUILT_Top_of_Concrete").value;
var GE = +getField("ASBUILT_Ground_Elevation").value;
// If DP is N/A, set this field to display N/A
If (DP === N/A); {
event.value = "NA"; // display N/A in this field
} else
{
//...otherwise, set this field value to the result of the following calculation
event.value = ((TC - GE) * 1000);
}