JS判断RadioButton是否选中
<asp:RadioButton ID="RadioYes" runat="server" Text="同意" />
<br />
<asp:RadioButton ID="RadioNo" runat="server" Text="不同意"/>
判断这俩个第一个选中
<asp:Button ID="BtnUpLoad" runat="server" Text="上传" onclick="BtnUpLoad_Click"
Enabled="False" />
的Enabled为true 第二个选中Enabled为false

[解决办法]

HTML code

<script type="text/javascript">    function is()    {    if(document.getElementById("RadioYes").checked==true)    {    alert("YES");    document.getElementById('BtnUpLoad').disabled=document.getElementById('RadioYes').checked;     }    else if(document.getElementById("RadioNo").checked==true)    {    alert("NO");    document.getElementById('BtnUpLoad').disabled=document.getElementById('RadioYes').checked;    }    }    </script><asp:RadioButton  ID="RadioYes" runat="server" Text="同意" onclick="is()" />                               <br />                             <asp:RadioButton  ID="RadioNo" runat="server" Text="不同意" onclick="is()"/>