Adobe Dreamweaver CS3 - Manual (Page 372)

DREAMWEAVER CS3
User Guide
365
If you are validating multiple fields when the user submits the form, the onSubmit event automatically appears in
the Events menu.
10 If you are validating individual fields, check that the default event is onBlur or onChange . If not, select one of
those events.
Both events trigger the Validate Form behavior when the user moves away from the field. The difference is that
onBlur occurs whether or not the user has typed in the field, and onChange occurs only if the user changed the
contents of the field. The onBlur event is preferred if the field is required.
September 4, 2007