大神们，为什么要用.lastChild，还有新增行的函数里要再次调用Highlight();

  <script type="text/javascript">  

window.onload = function(){

Highlight();

}  

function addOne(obj){ 

    var tbody = document.getElementById('table').lastChild;  

var tr = document.createElement('tr');  

var td = document.createElement("td");

td.innerHTML = "<input type='text'/>";

tr.appendChild(td);

td = document.createElement("td");  

td.innerHTML = "<input type='text'/>";

tr.appendChild(td);

td = document.createElement("td");

td.innerHTML = "<a href='javascript:;' onclick='deleteRow(this)'>删除</a>";

tr.appendChild(td);   

tbody.appendChild(tr);   

Highlight();

    }

function deleteRow(obj){

    var tbody = document.getElementById('table').lastChild;  

var tr = obj.parentNode.parentNode;

tbody.removeChild(tr);

}

function Highlight(){

var tbody = document.getElementById('table').lastChild;

trs = tbody.getElementsByTagName('tr');   

for(var i =1;i<trs.length;i++){

trs[i].onmouseover = function(){

this.style.backgroundColor ="#f2f2f2";

} 

trs[i].onmouseout = function(){

this.style.backgroundColor ="#fff";

} 

}  

}

  </script>