jquery模拟a标签的click事件,无法实现跳转

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问题描述

使用jquery模拟a标签的click事件,无法触发其默认行为。即click()或trigger('click')无法触发href跳转。

<a id="aBtn" href="https://www.car-me.com/">去卡咪官网</a>
$('#aBtn').click();//无法跳转,不生效
$('$aBtn').trigger('click');//同样无法跳转,不生效

问题原因

jquery内部实现click或trigger方法时,并未真正模拟用户点击事件,只是模拟了事件对象及冒泡的触发。(最后附有jquery实现源码供参考)

解决方案

解决思路:在原生dom触发click事件或利用事件冒泡来解决。

  1. 原生dom触发click
<a id="aBtn" href="https://www.car-me.com/">去卡咪官网</a>
document.querySelector('#aBtn').click();//原生dom触发 或者
$('#aBtn')[0].click();//jquery对象转为dom对象再触发
  1. 利用子元素事件冒泡
<a id="aBtn" href="https://www.car-me.com/">
    <span id="spanBtn">去卡咪官网</span>
</a>
$('#spanBtn').click();//或者
$('#spanBtn').trigger('click');
jquery trigger()实现源码(8159行-8304行)

源码链接地址

关键摘要:

// 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()时,会调用缓存列表里的事件回调函数,但未执行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(),会执行elem.click()******
			elem[ type ]();

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

			jQuery.event.triggered = undefined;

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