Addition calc inaccurate when one element is zero value

Explicitly convert each value to a number using the unary + operator to avoid string concatenation:

// Get field values, as numbers
var policy = +getField("num.SS.Expense.Title.Policy").value
var search = +getField("num.SS.Expense.Title.Search").value
var tax = +getField("num.SS.Expense.Title.StateFee").value
var cpl = +getField("num.SS.Expense.Title.CPL").value

I think you will find the value is not zero but a null character string. You are assuming an empty field is a numeric zero, but it usually is a null character string,and when the '+' operator is used with any character string value including a null strings, JavaScript assumes you want to concatenate the strings and not add them. Using the multiplicative identity (1) , additive identity (0), or the Number constrictor will force any number stored as a character string to a number and for a null character string force the value to numeric zero.

You can use:

var policy = this.getField("num.SS.Expense.Title.Policy").value
var search = this.getField("num.SS.Expense.Title.Search").value
var tax = this.getField("num.SS.Expense.Title.StateFee").value
var cpl = this.getField("num.SS.Expense.Title.CPL").value

event.value = policy + search + cpl + tax

// added code for debugging:
console.show();
console.clear();
console.println('typeof policy: ' + typeof policy);
console.println('typeof search: ' + typeof search);
console.println('typeof tax: ' + typeof tax);
console.println('typeof cpl: ' + typeof cpl);
console.println('typeof total: ' + typeof event.value);

To see what the type of data, number or string, is being processed.

Thank you both for your help and very thorough responses.

Ooops, not done yet. I employed a technique from John Dubert's book that blanks a field using
if(a + b + c = 0)
event.value = ""
else
event.value = a + b + c

...to avoid unsightly zeros in fields. However, as revealed by the debugging code, doing that causes the field value to be treated as a string instead of a number, and therefore I'm right back where I started. I could write the code to hide the field if the value is 0.00, but is there another way to solve the issue that you might recommend?

The '=' operator is not the equality operator. So your code will never work as expected.

Are you getting any errors on the JS debugging console?

What result are you getting?

I would force the values for 'a', 'b', and 'c' to a number before performing any computation.

duplicate post.

First, I apologize for 2 things: (1) I misunderstood George Johnson's suggestion; did not grasp what he was saying (working too late, I suppose). (2) In my last post before this reply, I misstated Dubert's technique for avoiding displaying zero's, which should be this:

if(a + b +c != 0)

event.value = a + b + c
else
event.value = ""

Without the unary + operator Dubert's technique results in a null character string and causes concatenation, but once I add the unary + operator, Dubert's technique works without concatenation, as revealed by George Kaiser's very helpful debugging code.