变换td底色

Question

<table width="100" border="0" cellspacing="0" cellpadding="0" onclick=TDClick()>
  <tr id=tr>
    <td>td1</td>
    <td>td2</td>
    <td>td3</td>
    <td>td4</td>
    <td>td5</td>
  </tr>
</table>
<SCRIPT LANGUAGE="JavaScript">
<!--
function TDClick()
{
var obj = event.srcElement;
if(obj.tagName!="TD")
return;
for(var i = 0; i < tr.cells.length; i++)
tr.cells[i].style.backgroundColor = "white";
obj.style.backgroundColor = "red";
}
//-->
</SCRIPT>

Answer 1

<table border=1><tr><td id=D1>123</td></tr></table>
<input type=button value=change onclick="D1.style.backgroundColor='blue';">

Answer 2

<script language=javascript>
function chcolor(cobj,color)
{
   var t=cobj.parentNode.parentNode;
   for (var i=0;i<t.rows.length;i++)
      for(var j=0;j<t.rows[i].cells.length;j++)
         t.rows[i].cells[j].style.backgroundColor='';   cobj.style.backgroundColor=color;
}
</script><table border=1>
<tr>
  <td style="background-color:#008000" onclick="chcolor(this,'#008000')">111</td>
  <td onclick="chcolor(this,'#008000')">111</td>
  <td onclick="chcolor(this,'#008000')">111</td>
</tr>
<tr>
  <td onclick="chcolor(this,'#008000')">111</td>
  <td onclick="chcolor(this,'#008000')">111</td>
  <td onclick="chcolor(this,'#008000')">111</td>
</tr>
<tr>
  <td onclick="chcolor(this,'#008000')">111</td>
  <td onclick="chcolor(this,'#008000')">111</td>
  <td onclick="chcolor(this,'#008000')">111</td>
</tr>
</table>