Currency operations with javaScript?

Question

I\'m creating a budget application with javascript. I have to let javascript do most of the operations. So I have some controls where the user changes the desired amount for

Answer 1

Always with currency keep track of it as integers internally. All operations should be done on integers. Only have the decimal for display.

check out this fiddle if you are thinking about using decimal points to keep track of money.

Answer 2

Binary floating-point numbers are inept at handling decimal fractions, so 0.1 + 0.2 is not equal to 0.3. This is the most frequently reported bug in JavaScript, and it is an intentional consequence of having adopted the IEEE Standard for Binary Floating-Point Arithmetic (IEEE 754). This standard is well-suited for many applications, but it violates most of the things you learned about numbers in middle school. Fortunately, integer arithmetic in floating point is exact, so decimal representation errors can be avoided by scaling. For example, dollar values can be converted to whole cents values by multiplying them by 100. The cents then can be accurately added. The sum can be divided by 100 to convert back into dollars. People have a reasonable expectation when they count money that the results will be exact.

"JavaScript: The Good Parts by Douglas Crockford. Copyright 2008 Yahoo! Inc., 978-0-596-51774-8."