jQuery：对象检查属性不会更新

是不是jQuery对象一直没有更新属性更改？

<input type="checkBox" checked="checked" id="cb"
   onclick   = "getVal('click')"
   onchange  = "getVal('change')"
   onmouseup = "getVal('mouseup')"
/> Foo

var global = jQuery('#cb');
function getVal(msg){

   var local = jQuery('#cb');
   var s     = '      ';

   alert( 'Event: ' + msg + '\n'
        + s + s + s + s + s + ' _local_' + s + s + '_global_\n'
        + ".is(':checked')\t\t " + t(local.is(':checked'))   + t(global.is(':checked'))  + '\n'
        + ".attr('checked')\t "  + t(local.attr('checked'))  + t(global.attr('checked')) + '\n'
        + ".prop('checked')\t "  + t(local.prop('checked'))  + t(global.prop('checked')) + '\n'
        );
}


function t(val){
    var l = (val+'').length;
    return (val + '' + (l>'false'.length?'\t':(l='checked'.length?'\t\t':'\t\t\t\t')));
}