Is it possible to use extensive formulas (e.g. "if" or vlookup functions) in the "Custom Calculation Script"?

Question

I am working on a form fill PDF converted from MS excel. This is for others to use who don't have MS excel that need to use my spreadsheet.
1. I would like to know how complex can the formulas be in the custom calculation script in the calculate tab under properties in a cell menu?
2. Where can I find what formulas will work in the custom calculation script along with the format for those formulas to work correctly (tutorials would help)?
I have tried writing an "if" function but received and error so I am assuming either functions don't work in the script or there is a different format than standard spreadsheet formats.
Bruce

Answer 1

In that case the for loop would be:
    for (var i = 0; i < 8; i += 1) {
        sum += +getField("Total." + i).value;
So initially, the counter i is equal to zero, so the field name used with the getField method is:
"Total." + 0, which results in the string "Total.0". With each iteration, the variable i is incremented by 1, so the subsequent field names are the following:
"Total.1"
"Total.2"
"Total.3"
"Total.4"
"Total.5"
"Total.6"
"Total.7"
The script gets the value of each field, converts it to a number, and adds the number it to the running sum.