checkboxlist select only one item
<p>I am trying to select only one checkbox from the list. Here is the code I am trying but it doesn't seem to be working.  I can use RadioButtonlist but it doesn't allow me to deselect the radio button. Please let me know.</p>

<pre><code>$(document).ready(function () {
var checkboxlistid = "#&lt;%= chkLst.ClientID %&gt;"; 
$(checkboxlistid + " input:checkbox").click(function () { 
 $(this).attr("checked",""); });
</code></pre>

<p>});</p>

<pre><code>                    &lt;asp:CheckBoxList ID="chkLst" runat="server" RepeatDirection="Horizontal"&gt;
                        &lt;asp:ListItem Value="U"&gt;Unknown&lt;/asp:ListItem&gt;
                        &lt;asp:ListItem Value="R"&gt;Ref&lt;/asp:ListItem&gt;
                    &lt;/asp:CheckBoxList&gt;
</code></pre>
