关于target currentTarget 属性的解析（官方收集）
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这是从官方的文章中感觉重要的一个个片段中截取出来的，可能有些东西不是一个页面的。也许有的是在说明Flex时说的，也许是在解说AS3时候说的。 自己感觉挺不错的，就收集了起来。 自己尝试过翻译一下下面的文章，但总是感觉不够“原汁原味” ，其中的单词并不难，有兴趣的可以看看吧。 About the target and currentTarget properties Every?Event?object has a?target?and a?currentTarget?property that help you to keep track of where it is in the process of propagation. The?target?property refers to the dispatcher of the event. The?currentTarget?property refers to the current node that is being examined for event listeners. MouseEvent events bubble up the parent chain,and can be handled on any ancestor. As the event bubbles,the value of the?event.target?property stays the same (UITextField),but the value of the?event.currentTarget?property is set at each level to be the ancestor that is handling the event. Eventually,the?currentTarget?will be Button,at which time the Button control's event listener will handle the event. For this reason,you should use the?event.currentTarget?property rather than the?event.target?property Capturing phase During the capturing phase,Flex changes the value of the?currentTarget?property on the Event object to match the current node whose listener is being called. The?target?property continues to refer to the dispatcher of the event. Targeting phase In the targeting phase,Flex invokes the event dispatcher's listeners. No other nodes on the display list are examined for event listeners. The values of the?currentTarget?and the?targetproperties on the Event object during the targeting phase are the same. Bubbling phase? In the bubbling phase,Flex examines an event's ancestors for event listeners. Flex starts with the dispatcher's immediate ancestor and continues up the display list to the root ancestor. This is the reverse of the capturing phase. During the bubbling phase,Flex changes the value of the?currentTarget?property on the Event object to match the current node whose listener is being called. The?target?property continues to refer to the dispatcher of the event. When Flex invokes an event listener,the Event object might have actually been dispatched by an object deeper in the display list. The object that originally dispatched the event is the?target. The object that the event is currently bubbling through is the?currentTarget. So,you should generally use the?currentTarget?property instead of the?target?property when referring to the current object in your event listeners. （编辑：李大同） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |