一个简单功能,大家帮我解一下,在线等
当焦点在文本框amount时,文本框后面的文字加上一个样式,当焦点离开文本框amount时,文本框后面的样式去掉,请问function   clow()怎么写

代码如下:
<table   width= "100% "   border= "0 "   cellspacing= "0 "   cellpadding= "0 ">
                <tr>
                    <td   width= "16% "> <input   name= "amount "   type= "text "   id= "amount "   onFocus= "clew() "   onKeyPress= "javascript:CheckNum(); "   value= " <%=cc( "total ")%> "   size= "20 "   maxlength= "20 "> &nbsp;&nbsp;&nbsp; </td>
                    <td   width= "84% "> <div   style= "   background-color:#FFdddd;width:400;line-height:23px;border-style:solid;   border-width:   1pt;border-color:#ff0000 "> &nbsp;库仓还有该材料库存 <b> <font   color=red> <%=cc( "amount ")%> </font> </b> ,计划生产产品数 <b> <font   color=red> <%=cc( "plannum ")%> </font> </b> </div> </td>
                </tr>
            </table>

------解决方案--------------------
请加上这个
document.getElementsByTagName( "div ")[0].className= 'a ';