在上一篇《jQuery学习-事件之绑定事件（一）》我们了解了jQuery的add方法，今天我们来学习下dispatch方法：
dispatch: function( event ) {
//这里是修正event对象的属性，处理兼容性问题
event = jQuery.event.fix( event );
var i, ret, handleObj, matched, j,
handlerQueue = [],//事件队列
args = slice.call( arguments ),//获取第一参数为event
handlers = ( jQuery._data( this, "events" ) || {} )[ event.type ] || [],//从缓存系统中获取改标签的事件对象
special = jQuery.event.special[ event.type ] || {};// 对象用于某些事件类型的特殊行为和属性
// Use the fix-ed jQuery.Event rather than the (read-only) native event
args[0] = event;
event.delegateTarget = this;
// Call the preDispatch hook for the mapped type, and let it bail if desired
if ( special.preDispatch && special.preDispatch.call( this, event ) === false ) {
return;
}
// Determine handlers
handlerQueue = jQuery.event.handlers.call( this, event, handlers );//处理事件队列，过滤，排序等操作
//先运行代理事件，且没有阻止冒泡
i = 0;
while ( (matched = handlerQueue[ i++ ]) && !event.isPropagationStopped() ) {
event.currentTarget = matched.elem;
j = 0;
while ( (handleObj = matched.handlers[ j++ ]) && !event.isImmediatePropagationStopped() ) {//在这里我们取出了在绑定事件的组合的对象
// Triggered event must either 1) have no namespace, or
// 2) have namespace(s) a subset or equal to those in the bound event (both can have no namespace).
if ( !event.namespace_re || event.namespace_re.test( handleObj.namespace ) ) {
event.handleObj = handleObj;
event.data = handleObj.data;//在这里我们可以在执行事件的时通过event.data来访问自定的数据
//真正触发执行事件的地方
ret = ( (jQuery.event.special[ handleObj.origType ] || {}).handle || handleObj.handler )
.apply( matched.elem, args );
if ( ret !== undefined ) {
if ( (event.result = ret) === false ) {
event.preventDefault();//阻止默认行为
event.stopPropagation();//阻止冒泡
}
}
}
}
}
//特殊事件的处理
if ( special.postDispatch ) {
special.postDispatch.call( this, event );
}
return event.result;
}
好了，今天就到这里了，一点一点偷！