ASP Forms - Disabling fields when an option from drop down is selected

[insane_mad_maniak]

I have the following form code:http://pastebin.com/FQZ8d5UDWhich is implemented at:http://minebook.net/m/If you navigate to the second tab of the above link, when the option "Variable" is selected from the drop down, I want all other fields to disable.My Javascript code is as follows:http://pastebin.com/zFCzrgDRI have had many vain attempts at this. Thank you in advance.