selected radio button again

selected radio button again

I using jquery-1.10.2 to select two radio button like blow,it is not work ,but using jquery-1.8.3.min.js is correct,who can help me how todo it,tks:

<script>
function testradio(radval)
{
  $("input:radio[name='radisstop'][value='"+radval+"']").attr("checked",true);
}

</script>
<input type="radio" name="radisstop" CHECKED value="1" id="isstop_0"><label for="isstop_0">running</label>
<input type="radio" name="radisstop" value="2" id="isstop_1"><label for="isstop_1">stop</label>

<input type="button" value="1" onclick="javascript:testradio('1');">
&nbsp;&nbsp;
<input type="button" value="2" onclick="javascript:testradio('2');">