下面的代码运行后的结果应该是200,可怎么显示undefined呀? 郁闷~帮忙看一下吧.谢谢~ [php] <?php if(isset($_GET['id'])){ $data = array('a' => 200 , 'b' => array('id'=>2 , 'name' => '512')); echo json_encode($data); } ?>[/php] <script language="javascript"> function InitAjax() { var ajax=false; try { ajax = new ActiveXObject("Msxml2.XMLHTTP"); } catch (e) { try { ajax = new ActiveXObject("Microsoft.XMLHTTP"); } catch (E) { ajax = false; } } if (!ajax && typeof XMLHttpRequest!='undefined') { ajax = new XMLHttpRequest(); } return ajax; } function getNews() { var url = "json.php?id=1"; var show = document.getElementById("show_news"); var ajax = InitAjax(); ajax.open("GET", url, true); ajax.onreadystatechange = function() { if (ajax.readyState == 4 && ajax.status == 200) { var j=eval("ajax.responseText"); show.innerHTML = j.a; } } ajax.send(null); } </script> json