<a id="aBtn" >去卡咪官網</a>
$('#aBtn').click();//無法跳轉，不生效
$('$aBtn').trigger('click');//同樣無法跳轉，不生效

<a id="aBtn" >去卡咪官網</a>
document.querySelector('#aBtn').click();//原生dom觸發 或者
$('#aBtn')[0].click();//jquery對象轉為dom對象再觸發

<a id="aBtn" >
 <span id="spanBtn">去卡咪官網</span>
</a>
$('#spanBtn').click();//或者
$('#spanBtn').trigger('click');

// Fire handlers on the event path （8237行）
i = 0;
while ( ( cur = eventPath[ i++ ] ) && !event.isPropagationStopped() ) {
	lastElement = cur;
	event.type = i > 1 ?
		bubbleType :
		special.bindType || type;

	// jQuery handler
	handle = ( dataPriv.get( cur, "events" ) || {} )[ event.type ] &&
		dataPriv.get( cur, "handle" );
	if ( handle ) {
	//******自身trigger('click')或click()時,會調用緩存列表里的事件回調函數,但未執行elem.click()******
		handle.apply( cur, data );
	}

	// Native handler
	handle = ontype && cur[ ontype ];
	if ( handle && handle.apply && acceptData( cur ) ) {
		event.result = handle.apply( cur, data );
		if ( event.result === false ) {
			event.preventDefault();
		}
	}
}

// If nobody prevented the default action, do it now （8263行）
if ( !onlyHandlers && !event.isDefaultPrevented() ) {

	if ( ( !special._default ||
		special._default.apply( eventPath.pop(), data ) === false ) &&
		acceptData( elem ) ) {

		// Call a native DOM method on the target with the same name as the event.
		// Don't do default actions on window, that's where global variables be (#6170)
		if ( ontype && isFunction( elem[ type ] ) && !isWindow( elem ) ) {

			// Don't re-trigger an onFOO event when we call its FOO() method
			tmp = elem[ ontype ];

			if ( tmp ) {
				elem[ ontype ] = null;
			}

			// Prevent re-triggering of the same event, since we already bubbled it above
			jQuery.event.triggered = type;

			if ( event.isPropagationStopped() ) {
				lastElement.addEventListener( type, stopPropagationCallback );
			}
   //******子元素trigger('click')或click()，會執行elem.click()******
			elem[ type ]();

			if ( event.isPropagationStopped() ) {
				lastElement.removeEventListener( type, stopPropagationCallback );
			}

			jQuery.event.triggered = undefined;

			if ( tmp ) {
				elem[ ontype ] = tmp;
			}
		}
	}
}