event对象具有的方法

//
dataTransfer,
toElement,
fromElement,
y,
x,
offsetY,
offsetX,
webkitMovementY,
webkitMovementX,
relatedTarget,
button,
metaKey,
altKey,
shiftKey,
ctrlKey,
clientY,clientX,screenY,screenX,
which,pageY,pageX,layerY,layerX,
charCode,keyCode,
detail,view,clipboardData,
cancelBubble,returnValue,
srcElement,defaultPrevented,timeStamp,
cancelable,bubbles,eventPhase,currentTarget,target,type,initMouseEvent,initUIEvent,stopPropagation,preventDefault,
initEvent,stopImmediatePropagation,
NONE,CAPTURING_PHASE,AT_TARGET,BUBBLING_PHASE,MOUSEDOWN,MOUSEUP,MOUSEOVER,MOUSEOUT,MOUSEMOVE,MOUSEDRAG,CLICK,DBLCLICK,KEYDOWN,KEYUP,KEYPRESS,DRAGDROP,FOCUS,BLUR,SELECT,CHANGE