onmouseover Property
Returns or sets a Variant that represents the value of the onmouseover attribute that is the name of the script to run when the onmouseover event fires.
expression.onmouseover
expression Required. An expression that returns one of the objects in the Applies To list.
Example
The following example sets the onmouseover attribute for the BODY element in the active document.
ActiveDocument.body.onmouseover = "script()"