event对象

IE9 FF CHROME

<button type="button" id="button" class="btn" name="button">click</button><script type="text/javascript">var oBtn=document.getElementById("button");oBtn.onclick=function(event){    console.log(event.target) // <button id="button" class="btn" name="button" type="button">    console.log(event.srcElement.className) //btn}</script>

IE6-8

<button type="button" id="button" class="btn" name="button">click</button><script type="text/javascript">var oBtn=document.getElementById("button");oBtn.onclick=function(event){    var event=window.event;    console.log(event.srcElement) // <button id="button" class="btn" name="button" type="button">    console.log(event.srcElement.className) //btn}</script>

兼容

<button type="button" id="button" class="btn" name="button">click</button><script type="text/javascript">var oBtn=document.getElementById("button");oBtn.onclick=function(event){    var event=event || window.event;    obj = event.srcElement ? event.srcElement : event.target;    console.log(obj.id)}</script>