You might come across an older RDF file that has a qualified-ancestor element similar to.
可能还会遇到更老的RDF文件，使用类似的限定的祖先元素。
In this case, the selector is the ancestor element name followed by the descendant element name.
在这种情况下，选择符是祖先元素名后面跟着后代元素名。
The browser has to go through every single ancestor element of the event target to see if it has an event handler.
因为浏览器总是检查所有目标元素的上层元素，去寻找相应的事件处理器。
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