Form Validation Script for >0

I need to enter a form validation script that will allow a user to enter a value greater than OR less than zero, but never equal to zero.  I know the following works for the "greater than" side, but I need assistance on how to incorporate the "less than" part:

event.rc=event.value>0;if(!event.rc)
app.alert("Value cannot equal 0");

Please help.  Thanks!