用javascript,怎么获得表格中所点击的这一行的行数
我想获得所点击的某行,在表格中是排在第几行,应该要怎么得到? 
 我要实现的是:在某一行最后的一个单元格按回车,光标就跳到下一行的第一个单元格;   
 只要我获得了,当前的行是第几行,就可以知道下一行是处于表格的第几行(不知有没有其它的方法); 
 该怎么做,请大家帮帮忙,
------解决方案-------------------- <table width= "100% " cellspacing= "0 " cellpadding= "0 ">  
  <tr>  
  <td> 0 </td>  
  </tr>  
  <tr id= "ro1 ">  
  <td> 1 </td>  
  </tr>  
  <tr>  
  <td> 2 </td>  
  </tr>  
  </table>  
  <script type= "text/javascript ">  
 var line = document.getElementById( "ro1 "); 
 var i = line.rowIndex, n = line.parentNode.rows[i + 1]; 
 alert(line.innerHTML +   "\n " + (n ? n.innerHTML :  "尾行的说 ")); 
  </script>
------解决方案--------------------首先取得出发事件的td对象(tdx) 
 tdx.parentNode.nextSibling.firstChild这个对象就是下一行的第一td对象.
------解决方案-------------------- <script language= "javascript ">  
 function showlinenum(obj){ 
   var rownum = obj.rowIndex 
   document.all.dd.value=rownum; 
 }   
  </script>  
  <body>  
  <table width= "280 " border= "2 " cellspacing= "1 " cellpadding= "2 ">  
    <tr onMouseOver= "showlinenum(this) ">  
      <td>   </td>  
      <td>   </td>  
      <td>   </td>  
    </tr>  
    <tr onMouseOver= "showlinenum(this) ">  
      <td>   </td>  
      <td>   </td>  
      <td>   </td>  
    </tr>  
    <tr onMouseOver= "showlinenum(this) ">  
      <td>   </td>  
      <td>   </td>  
      <td>   </td>  
    </tr>  
  </table>  
  <p>  
    <input name= "dd " type= "text " id= "dd " />    
 点击的话就换成onclick== "showlinenum(this) "
------解决方案-------------------- <!DOCTYPE HTML PUBLIC  "-//W3C//DTD HTML 4.0 Transitional//EN ">  
  <HTML>  
  <HEAD>  
  <TITLE>  New Document  </TITLE>  
  <META NAME= "Generator " CONTENT= "EditPlus ">  
  <META NAME= "Author " CONTENT= " ">  
  <META NAME= "Keywords " CONTENT= " ">  
  <META NAME= "Description " CONTENT= " ">  
  </HEAD>  
  <BODY>  
  <FORM METHOD=POST ACTION= " ">  
  <TABLE border=1 width=300 height=300>  
  <TR>  
 	 <TD>   </TD>  
 	 <TD>   </TD>  
 	 <TD>   </TD>  
  </TR>  
  <TR>  
 	 <TD>   </TD>  
 	 <TD>   </TD>  
 	 <TD>   </TD>  
  </ <TR>    
  <TR>  
 	 <TD>   </TD>  
 	 <TD>   </TD>  
 	 <TD>   </TD>  
  </TR>    
  <TR>  
 	 <TD>   </TD>  
 	 <TD>   </TD>  
 	 <TD>   </TD>  
  </TR>    
  <TR>  
 	 <TD>   </TD>  
 	 <TD>   </TD>  
 	 <TD>   </TD>