Dom多事件注册
今天看到这样一段代码，如下:

/* 监听document/window对象上的click、mousedown、load、mouseup、mousemove事件 */Page.onClick = function(fun) {Sky.EventManager.addEvent(document, "click", fun);}Page.onLoad = function(fun, index) {Sky.EventManager.addEvent(window, "load", fun, index);}Page.onMouseDown = function(fun) {Sky.EventManager.addEvent(document, "mousedown", fun);}Page.onMouseUp = function(fun) {Sky.EventManager.addEvent(document, "mouseup", fun);}Page.onMouseMove = function(fun) {Sky.EventManager.addEvent(document, "mousemove", fun);}Page.onKeyDown = function(fun) {Sky.EventManager.addEvent(document, "keydown", fun);}