Event Flow
Consider the situation when there are 2 elements nested together. Both have event handlers registered on the same event type, say "click". When the user clicks on the inner element, there are two possible ways to handle it:
- Trigger the elements from outer to inner (event capturing). This model is implemented in Netscape Navigator.
- Trigger the elements from inner to outer (event bubbling). This model is implemented in Internet Explorer and other browsers.
W3C takes a middle position in this struggle. Events are first captured until it reaches the target element, and then bubbled up. During the event flow, an event can be responded to at any element in the path (an observer) in either phase by causing an action, and/or by stopping the event (with method event.stopPropagation for W3C-conforming browsers and command event.cancelBubble = true for Internet Explorer), and/or by cancelling the default action for the event.
Read more about this topic: DOM Events
Famous quotes containing the words event and/or flow:
“The hero sees that the event is ancillary: it must follow him.
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—Ralph Waldo Emerson (1803–1882)
“Parents ought, through their own behavior and the values by which they live, to provide direction for their children. But they need to rid themselves of the idea that there are surefire methods which, when well applied, will produce certain predictable results. Whatever we do with and for our children ought to flow from our understanding of and our feelings for the particular situation and the relation we wish to exist between us and our child.”
—Bruno Bettelheim (20th century)