Help!! Javascript calculation is giving me the wrong answer, why?

Question

I'm trying to use javascript to calculate monthly payment of a loan with an interest rate of 14.4%.
If you borrow 1000 for 2yrs you should pay abt 48 per month. My formula is however giving 18 instead of 48. When i try with excel it's working fine. Please tell me what is wrong or give me a working code from any other language. Am using asp server.

See the pmt formula at: http://www.1728.com/loanform.htm

Here is my code which you can copy&paste for testing:



principal:

years:



monthly pymt:

Answer 1

You could use parse float or you could do it just with eval()

Working code:

Answer 2

Use parseFloat( ) to get value from Principal text box.