I'm brand new to javascript and I'm muddling my way through it. I've made an online calculator that actually works pretty well except for one problem. Here's the calculator:

http://www.oregonblackbook.com/farms/bidcalc.html

The problem is this: if you enter numbers into the "Basic Bid" section, and then enter zeros into the "Advanced Bid" section, it should calculate the "basic bid charge" based on the numbers in the first section. The "Total Charge for Advanced Bid" should be zero, and then "total bid" should add basic and advanced together, which in this case would make it the same number as "basic bid charge". In theory anyways. But for some reason it's adding a zero on the end, an extra decimal place, and I can't for the life of me figure out why.

Could anyone help with this? Thank you!