How to check and uncheck all checkboxes inside a div

I want to uncheck all checkboxex inside the 'test' div without those checkboxes whose attributes are disabled.

    <div id="test">
            <input type="checkbox" id="check1" name="check1">
            <input type="checkbox" id="check01" name="check01" disabled="disabled">
            <input type="checkbox" id="check2" name="check2" disabled="disabled">
            <input type="checkbox" id="check3" name="check3">
            <input type="checkbox" id="check4" name="check4">
            <input type="checkbox" id="check50" name="check50">
            <input type="checkbox" id="check6" name="check6">   
        </div>
        <input type="button" id="uncheckAll" onclick="uncheckAll('test')">
<script language="javascript">
  function uncheckAll()
{
  $('#'+divid+' :checkbox').attr('checked',false);
  /*
   This function uncheck all of the checkboxes, which i don't want, i want to
   uncheck only checkboxes whose attributes are not disabled.
  /*
}
</script>