表格行数不确定,如何为表格最后一行指定样式?
如题
------解决方案--------------------用javascript
------解决方案-------------------- <html>  
  <head>  <title> 测试 </title>  </head>  
  <style type= "text/css ">  
 .bb{ 
 border-color:red; 
 } 
  </style>  
  <body>  
  <table width=200 border=1 height=300 cellpadding=0 cellspacing=0  id= "tb1 ">    
  <tr>  <td>  DDD </td>  <td>  bbb </td>  </tr>  
  <tr>  <td>  ddd </td>  <td>  BBB </td>  <tr>  
  <tr>  <td >  CCC </td>  <td>  AAA </td>  <tr>  
  </table>  
  <input type= "button " value= "给表格最后一行设置样式 " id= "btn1 ">  
  <script>  
 document.all.btn1.onclick=function(){ 
 var tb1=document.getElementById( "tb1 "); 
 alert(tb1.lastChild.lastChild.previousSibling.innerHTML); 
 if(tb1.lastChild.lastChild.previousSibling){ 
 alert(tb1.lastChild.lastChild.previousSibling.childNodes.length); 
 for(i=0;i <tb1.lastChild.lastChild.previousSibling.childNodes.length;i++) 
 { 
  alert(tb1.lastChild.lastChild.previousSibling.childNodes[i].innerText); 
  tb1.lastChild.lastChild.previousSibling.childNodes[i].className= "bb ";    
  } 
 } 
 } 
  </script>  
  </body>  
  </html>