Attributes for <AREA ...>
onMouseOver = "script command(s)"
onMouseOut = "script command(s)"

Usage Recommendation
use it, but don't rely on it

onMouseOver and onMouseOut work similar to their counterparts in <A ...>. These event handlers are triggered when the mouse moves over the area (onMouseOver) and when it moves out from being over the area (onMouseOut).

<AREA HREF="freelance.html" ALT="Freelance" 
    COORDS="31,0,164,26" SHAPE=RECT 
    onMouseOver="alert('Mouse Over!')">

gives us

<AREA HREF="freelance.html" ALT="Freelance" 
    COORDS="31,0,164,26" SHAPE=RECT 
    onMouseOut="alert('Mouse Out!')">

gives us