js中addEventListener中第3个参数

 

functiondiv

<div id="id1" style="width:200px; height:200px; position:absolute; top:100px; left:100px; background-color:blue; z-index:4">
      <div id="id2" style="width:200px; height:200px; position:absolute; top:20px; left:70px; background-color:green; z-index:1"></div>
  </div>

addEventListener中的第三个参 数是useCapture, 一个bool类型。当为false时为冒泡获取(由里向外)，true为capture方式(由外向里)。

eg1：

 

document.getElementById('id1').addEventListener('click', function() { console.log('id1');}, false);

document.getElementById('id2').addEventListener('click', function() { console.log('id2');}, false);

点击id2的div结果是: id2， id1

 

 

document.getElementById('id1').addEventListener('click', function() { console.log('id1');}, false);

document.getElementById('id2').addEventListener('click', function() { console.log('id2');}, true);

结果是: id2, id1

 

 

document.getElementById('id1').addEventListener('click', function() { console.log('id1');}, true);

document.getElementById('id2').addEventListener('click', function() { console.log('id2');}, false);

结果是：id1，id2

 

 

document.getElementById('id1').addEventListener('click', function() { console.log('id1');}, true);

document.getElementById('id2').addEventListener('click', function() { console.log('id2');}, true);

结果是：id1，id2

 

 

From: http://blog.csdn.net/jijun7885417/article/details/7870348