dom事件属性

<table border="1">
 <tr id="example4">
  <td >TD One</td>
  <td>TD Two</td>
  <td >TD Three</td>
 </tr>
</table>
 <button onClick="insertTD();">Call insertTD()</button>
  <button onClick="inspect();">Call insertTD()</button>

<script type="text/javascript">

var TDCount = 0;

function insertTD(){

 var newTD = document.createElement("td");
 //newTD.setAttribute("onmouseover","a()",0);无效
 newTD.attachEvent("onmouseover", a);
 //newTD.onmouseover=a;可以,此为陈旧方法,主要向下兼容
 newTD.setAttribute("width","200");
 var newText = document.createTextNode("New Cell " + (TDCount++));
 newTD.appendChild(newText);

 var trElm = document.getElementById("example4");
 var refTD = trElm.getElementsByTagName("td").item(2);
 trElm.insertBefore(newTD,refTD);
 
}

function a(){
alert("ss");
}

function inspect(){
elm = document.getElementById("example4");

  var str = "";
  for (var i in elm){
    str += i + ": " + elm.getAttribute(i) + "\n";
  }
  alert(str);
}

</script>