Problem:

If an HTML "input" control (such text, radio button, etc) has "disabled" attribute, the value of this control doesn't return to CGI program.

Resolution:

All disabled controls on an HTML page return null/undefined values to the CGI script.  A disabled text input field that contains text, for example, does not return any text to the CGI program.  Likewise, a disabled radio button that is checked will not return the "on" value to the CGI.

This is the default behaviour.