In your select's onchange you call 'calcForm()'. js is case sensitive; it has to be 'calcform()'. As far as your wrong results are concerned, you will have to round them. js is not able to deal correctly with certain floating point numbers.
@PittimannFeb 15.2005 — #Hi![i]Originally posted by scragar [/i]
[B]also you have the text box called length, this is a word used by javscript itself(thus you are unable to retrive it's value). [/B][/QUOTE]Didn't mentioned that because it is no problem in this context. The value CAN be retrieved. But of course you are right: better to avoid using such a name.