Bulletproof mouse-wheel event handling

mousewheel.js

if ( event.hasOwnProperty('type') && event.type == 'DOMMouseScroll' ){                                                          
  // Zoom from mousewheel (Firefox)
}
else if ( event.type == 'mousewheel' && event.originalEvent.hasOwnProperty('wheelDeltaY') ) {                                   
  // ... (Chrome)
}
else if ( event.type == 'mousewheel' && event.originalEvent.hasOwnProperty('wheelDelta') ) {                                    
  // ... (Opera)
direction = ( event.originalEvent.wheelDelta > 0 ) ? 'up' : 'down'
}
else if ( event.originalEvent.hasOwnProperty('scale') ) {                                                                       
  //    ... (pinch)
}
else {
  // Ghetto browser.
}