function addEvent( obj, type, fn ) { 
  if ( obj.attachEvent ) { 
    obj['e'+type+fn] = fn; 
    obj[type+fn] = function(){obj['e'+type+fn]( window.event );} 
    obj.attachEvent( 'on'+type, obj[type+fn] ); 
  } else 
    obj.addEventListener( type, fn, false ); 
} 
function removeEvent( obj, type, fn ) { 
  if ( obj.detachEvent ) { 
    obj.detachEvent( 'on'+type, obj[type+fn] ); 
    obj[type+fn] = null; 
  } else 
    obj.removeEventListener( type, fn, false ); 
} 
function getEventTarget(e) {
    e = e || window.event;
    return e.target || e.srcElement;
}