[10分] 当焦点在一个文本框上时执行事件

Question

<input onfocus="document.getElementById('ctl00_cphMain_tblCreditCardNo').style.backgroundColor='#FF00000';" >

Answer 1

<input name="ctl00$cphMain$txbCreditCardNo" 
type="text" maxlength="16" 
id="ctl00_cphMain_txbCreditCardNo" onfocus="document.getElementById('ctl00_cphMain_tblCreditCardNo').style.backgroundColor='#FF00000';" style="font-family:Arial;font-size:9pt;width:125px;" />脚本错误：
无效的属性值

Answer 2

<form>
<table width="200" border="1" id="ctl00_cphMain_tblCreditCardNo">
  <tr>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
  </tr>
  <tr>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
  </tr>
  <tr>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
  </tr>
</table>
</form><input name="ctl00$cphMain$txbCreditCardNo" 
type="text" maxlength="16" 
id="ctl00_cphMain_txbCreditCardNo" 
onfocus="document.getElementById('ctl00_cphMain_tblCreditCardNo').bgColor='#FF00000';" 
style="font-family:Arial;font-size:9pt;width:125px;" />
给分吧

Answer 3

可以了不过我好像忘了另一件事，，，如果焦点离开，怎么恢复原样？麻烦hunshihaichong(混世害虫)再指点下。