请问一个在后台设置input type="text"的class的有关问题

请教一个在后台设置input type="text"的class的问题
样式表：

C# code

.imgbutton{    background: url(images/wxzw.jpg);    border-style: none;    width: 16px;    height: 15px;    background-repeat: no-repeat;    cursor: pointer;    font-size: 1px;    text-decoration: none;}.imgbutton2{    background: url(images/xzzw.jpg);    border-style: none;    width: 16px;    height: 15px;    background-repeat: no-repeat;    cursor: pointer;    font-size: 1px;    text-decoration: none;}

C# code

<input type="text" id="t1p1z11" name="t1p1z11" class="imgbutton" value="0" readonly="readonly">

C# code

<input type="text" id="t1p1z11" name="t1p1z11" class="imgbutton" value="0" readonly="readonly" runat="server">t1p1z11.Attributes["class"] = "imgbutton2";
[解决办法]
 = =楼主真坏。。用了我的建议一分没给我 5555