I made many HTML forms with Zope but now, I need checkboxes. If I try: <FORM action="handleForm"> <INPUT TYPE="checkbox" NAME="sugar" CHECKED>Sugar? <INPUT TYPE="checkbox" NAME="milk">Milk?<BR> <INPUT TYPE="submit" NAME="submit" VALUE="Order"> </FORM> The Python Script handleForm cannot run if Milk is unchecked. This is because HTML browsers only send the value of the checkbox if it is checked. The URL sent looks like: http://progress.netaktiv.com:9673/Tests/handleForm?sugar=on&submit=Order (do note there is no Milk) and the error message is: --------- Site Error An error was encountered while publishing this resource. Invalid request The parameter, milk, was omitted from the request. Make sure to specify all required parameters, and try the request again. --------- Of course, milk is in the parameters of the Python Script, but how can I say that it is optional and should default to false? Using "milk:boolean" as its name changes nothing. Zope 2.3.2 (source release, python 1.5.2, linux2)