NOTE : The following table shows only scriptable standard HTML elements. The event handlers are used as attributes in the element. For other scripting details, see the Scripting Object Models section.
<A>
  OnMouseMove Y IEx 3.0
  OnMouseOver Y Y Cougar
  OnMouseOut* Y Cougar
  OnClick Y Y Cougar
<AREA>
  OnMouseOver* Y Cougar
  OnMouseOut* Y Cougar
  OnClick This can be forced Cougar
<BODY>
  OnBlur* Y NS 3.0
  OnError* Y NS 3.0
  OnFocus* Y NS 3.0
  OnLoad Y Y Cougar
  OnUnLoad Y Y Cougar
<FORM>
  OnReset* Y Y Cougar
  OnSubmit Y Y Cougar
<FRAMESET>
  OnBlur* Y Frames are not yet part of any (even draft) HTML specification.
  OnError* Y
  OnFocus* Y
  OnLoad Y
  OnUnLoad Y Y
<IMG>
  OnAbort* Y NS 3.0
  OnError* Y NS 3.0
  OnLoad* Y NS 3.0
<INPUT>
  TYPE="button" OnClick Y Y Cougar
                OnFocus ? Y Cougar
  TYPE="checkbox" OnClick Y Y Cougar
                  OnFocus ? Y Cougar
  TYPE="password" OnSelect ? ? Cougar
                  OnFocus ? Y Cougar
                  OnBlur ? Y Cougar
  TYPE="radio" OnClick Y Y Cougar
               OnFocus ? Y Cougar
  TYPE="reset" OnClick Y Y Cougar
               OnFocus ? Y Cougar
  TYPE="submit" OnClick Y Y Cougar
                OnFocus ? Y Cougar
  TYPE="text" OnSelect ? ? Cougar
              OnBlur Y Y Cougar
              OnFocus Y Y Cougar
              OnChange Y Y Cougar
<SELECT>
  OnBlur Y Y Cougar
  OnChange Y Y Cougar
  OnClick ?
  OnFocus Y Y Cougar
<TEXTAREA>
  OnBlur Y Y Cougar
  OnChange Appears to work as OnBlur Y Cougar
  OnFocus Y Y Cougar
  OnSelect ? ? Cougar

Event handlers suffixed by a * character are JavaScript 1.1 events and are mostly only supported by Netscape v3.0 and above.

Specification details
Only mentioned in the above Comparison Table is the W3C 'Cougar' specification. This is the draft specification that came soon after the HTML 3.2 specification (codenamed 'Wilbur'). It was basically the HTML 3.2 specification, with added <OBJECT>, <APPLET> and scripting events. Frames have not yet made it into any HTML specifications (draft or otherwise) and so could not be labelled as being covered by any specification.

Where a '?' is put in the comparison box, it means that the event is claimed to be supported by either Netscape or Microsoft, but on testing, it wasn't supported. If there is no Y, or '?' in the comparison box, it means that the browser documentation does not make any claim to support the scripting event.
That doesn't mean to say that it wasn't tested to be sure.