1，bind 方法，最后一个参数fn是多余的
// Handle object literals
if ( typeof type === "object" ) {
for ( var key in type ) {
this[ name ](key, data, type[key], fn);
}
return this;
}
2，注释
// Add which for click: 1 === left; 2 === middle; 3 === right
应修改为
// Add which for mousedown/mouseup : 1 === left; 2 === middle; 3 === right
3，data方法，定义了局部变量internalKey，但后续代码仍然沿用jQuery.expando。
var internalKey = jQuery.expando, getByName = typeof name === "string", thisCache,
4，jQuery.event.add方法，arguments改为e，apply改为call 更好一些。因为只会传一个参数：事件对象。
elemData.handle = eventHandle = function( e ) {
// Discard the second event of a jQuery.event.trigger() and
// when an event is called after a page has unloaded
return typeof jQuery !== "undefined" && (!e || jQuery.event.triggered !== e.type) ?
jQuery.event.handle.apply( eventHandle.elem, arguments ) :
undefined;
};
5，基于 “勿重复检测浏览器” 原则，jQuery.event.add 以下代码
if ( elem.addEventListener ) {
elem.addEventListener( type, eventHandle, false );
} else if ( elem.attachEvent ) {
elem.attachEvent( "on" + type, eventHandle );
}
应该使用以下来替换
jQuery.addEvent = document.addEventListener ?
function( elem, type, handle ) {
if ( elem.addEventListener ) {
elem.addEventListener( type, handle, false );
}
} :
function( elem, type, handle ) {
if ( elem.attactEvent ) {
elem.attactEvent( "on" + type, handle );
}
};
事实上，jQuery中已经有了jQuery.removeEvent，却不知为何没有jQuery.addEvent。