这边走:
// bubbling is internal
trigger: function( event, data, elem /*, bubbling */ ) {
// Event object or event type
var type = event.type || event,
bubbling = arguments[3];
// Handle a global trigger
if ( !elem ) {
// Don't bubble custom events when global (to avoid too much overhead)
event.stopPropagation();
// Only trigger if we've ever bound an event for it
if ( jQuery.event.global[ type ] ) {
jQuery.each( jQuery.cache, function() {
if ( this.events && this.events[type] ) {
jQuery.event.trigger( event, data, this.handle.elem );
}
});
}
}
// ... snip ...
// Trigger the event, it is assumed that "handle" is a function
var handle = elem.nodeType ?
jQuery.data( elem, "handle" ) :
(jQuery.data( elem, "__events__" ) || {}).handle;
if ( handle ) {
handle.apply( elem, data );
}
var parent = elem.parentNode || elem.ownerDocument;
// ... snip ....
if ( !event.isPropagationStopped() && parent ) {
jQuery.event.trigger( event, data, parent, true );
} else if ( !event.isDefaultPrevented() ) {
// ... snip ...
jQuery.event.triggered = true;
target[ targetType ]();
}
}
这里发生的事情如下:
When trigger
称为 jQuery 检查事件是否正在全局触发($.trigger("event_name");
).
如果是not在全球范围内触发,and传播尚未停止and有问题的元素有一个父元素(!event.isPropagationStopped() && parent
) 然后 jQuery 在父元素上手动调用触发事件。
jQuery.event.trigger( event, data, parent, true );
还有很多事情正在发生——请参阅event.js https://github.com/jquery/jquery/blob/master/src/event.js在 jQuery 源代码中。