<!DOCTYPE html><html><head>?<meta charset="utf-8">?<title>DOM事件</title>?<style>??#btn2{???font-size:25px;???background-color:blue;??}??#btn3{???font-size:25px;???background-color:red;??}??#btn{???font-size:25px;???background-color:yellow;??}?</style></head><body><div id="box">?<input type="button" value="按鈕1" id="btn" onclick="showMes()">?<input type="button" value="按鈕2" id="btn2">?<input type="button" value="按鈕3" id="btn3"></div><script>function showMes(){?alert("通過HTML添加事件");}?var btn=document.getElementById('btn');?var btn2=document.getElementById('btn2');?var btn3=document.getElementById('btn3');?btn2.onclick=function(){?????//DOM0級(jí)?alert("通過DOM0級(jí)添加事件");}btn2.onclick=null;btn3.addEventListener('click',showMes,false);//DOM2級(jí)btn3.addEventListener('click',function(){alert(this.value);},false)//btn3.removeEventListener('click'showMes,false);</script></body></html>
為什么寫上 btn2.onclick=null;后，三個(gè)按鈕都不能觸發(fā)事件了？用DOM2級(jí)的removeEventListener()方法也是
狼與香辛料
2017-10-23 17:09:55
