JavaScript权威设计--事件冒泡，捕获，事件句柄，事件源，事件对象(简要学习笔记十八)

<div id="myDiv">
    <input type="button" value="点我" id="myBtn">
</div>

var btn=document.getElementById("myBtn");
btn.onclick=function(){

    document.getElementById("myDiv").innerHTML="Progress...";
}

var btn=document.getElementById("myBtn");
btn.onclick=function(){
    btn.onclick=null;//移除事件处理程序
    document.getElementById("myDiv").innerHTML="Progress...";
}

function eventHandler(e){
    //获取事件对象 
e = e || window.event;//IE和Chrome下是window.event FF下是e 
    //获取事件源 
var target = e.target || e.srcElement;//IE和Chrome下是srcElement FF下是target 
}

function eventHandler(e) {
    e = e || window.event;
    // 防止默认行为 
    if (e.preventDefault) {
        e.preventDefault();//IE以外 
    } else {
        e.returnValue = false;//IE 
        //注意：这个地方是无法用return false代替的 
        //return false只能取消元素 
    }
}

function myParagraphEventHandler(e) {
    e = e || window.event;
    if (e.stopPropagation) {
        e.stopPropagation();//IE以外 
    } else {
        e.cancelBubble = true;//IE 
    }
}

<ul id="ulT">
<li class="item1">fsda</li>
<li class="item2">ewre</li>
<li class="item3">qewe</li>
<li class="item4">xvc</li>
<li class="item5">134</li>
</ul>

document.getElementById("ulT").onclick = function  (event) {
    console.log(event.target);
    console.log(event.currentTarget);
}