<script type="text/javascript">
(function () {
        var ButtonGroup = YAHOO.widget.ButtonGroup;
        var onCheckedButtonChange = function (p_oEvent) {
        };
        YAHOO.util.Event.onContentReady("mediaFilterButtonsFieldset", function () {
            var oButtonGroup = new ButtonGroup("mediaFilterButtons");
            oButtonGroup.on("checkedButtonChange", onCheckedButtonChange);
        });
}());
</script>
<div id="resultInfo">
  <form id="button-example-form" name="button-example-form" method="post">
      <fieldset id="mediaFilterButtonsFieldset">
          <div id="mediaFilterButtons" class="yui-buttongroup ie7filter" style="z-index:11;">
            <div id="mediaFilterLabel">Go to</div>
            <input id="radio1" class="filter_but" type="radio" name="0" value="First" checked rel="0" >
            <input id="radio2"  class="filter_but" type="radio" name="2" value="Second" rel="2">
            <input id="radio3"  class="filter_but" type="radio" name="1" value="Third" rel="1">
          </div>
      </fieldset>
  </form>
</div>

These are my YUI buttons. They're just 3 radio buttons turned into "buttons"--literally. My question is this:

After people click the third button, I cannot manually check the first button anymore. How can I manually check "radio1"?

I tried JQuery: $("#radio1").attr("checked",true); But this didn't work. The third button still remained pressed down.