无法从jquery中的Json_encode获取值_course

<div class="post-text" itemprop="text"> <p>I have a file whichh is converting my php array to json</p> <pre><code>&lt;?php include('lib/db.php'); $cid = mysql_real_escape_string($_POST['id']); $q = rand(1, 2); $var = array(); $rs1 = mysql_query("select * from questions where qid='$q' and sub_id='$cid'"); while ($r1 = mysql_fetch_array($rs1)) { $var[] = array('qid' = &gt; $r1['qid'], 'question' = &gt; $r1['question'], 'ans' = &gt; $r1['ans1'], 'ans2' = &gt; $r1['ans2'], 'ans3' = &gt; $r1['ans3'], 'ans4' = &gt; $r1['ans4']); } print json_encode($var); ?&gt; </code></pre> <p>and the jquery code to load the value</p> <pre><code>$.ajax({ url: "getquestion.php", type: "POST", data: "id=" + id, cache: false, dataType: "json", success: function (data, jqXHR) { if (data == null) { alert('nothing'); } else { alert(data[0]); } } }); </code></pre> <p>But i am getting undefined in firebug console But i want the JSON value in jQuery variable.</p> </div>

如何使用Jquery AJAX从PHP json_encode读取JSON数据_course

<div class="post-text" itemprop="text"> <p>BEEN at this for days. Using jquery ajax to perform somethings and trying to get a json encoded response from my server. Not sure why this is now working for me.</p> <p>Below is my Javascript function</p> <pre><code>function checkFriendsEmail(friendsEmail){ var request = $.ajax({ url : 'http://localhost/loginsentology/serverside/checkfriendexist2.php', type: 'POST', data: { 'checkfriend' : 'checkfriend', 'friendsemail' : friendsEmail, }, success: function(data) { console.log(data); &lt;&lt;&lt;-- Comes back to my console as a JSON obj console.log(data.nouser); &lt;&lt;-- Comes back undefined } </code></pre> <p>I get this result in my console. { "nouser" : ["noUserExist"] } &lt;&lt;&lt;----- How do I grab this.</p> <p>MY PHP is below</p> <pre><code>$fdarray = array(); $_db = DB::getInstance(); $_query = $_db-&gt;query('SELECT * FROM users WHERE email = ? ', array($_POST['friendsemail'])); $results = $_query-&gt;results(); $numberOfRows = $_db-&gt;numberOfRows(); if ($numberOfRows == 0) { //$noUserExist = 'NoUserExist'; $fdarray['nouser'] = array(); array_push($fdarray['nouser'], 'noUserExist'); echo json_encode($fdarray); return false; } else { //friends email exist in users db --&gt; now we must check to see if friend has devices $friendsEmail = $results[0]-&gt;email; if ($_POST['friendsemail'] == $friendsEmail) { $id = $results[0]-&gt;id; $_db2 = DB::getInstance(); $_query2 = $_db2-&gt;query('SELECT * FROM devices WHERE userid = ? ', array($id)); $results2 = $_query2-&gt;results(); $numberOfRows2 = $_db2-&gt;numberOfRows(); if ($numberOfRows2 == 0) { //user has no devices attached to name $fdarray['userexist'] = array(); $fdarray['nodevices'] = array(); array_push($fdarray['userexist'], true); array_push($fdarray['nodevices'], 'noDevicesForUser'); echo json_encode($fdarray); return false; } else { $fdarray['userexist'] = array(); $fdarray['devices'] = array(); array_push($fdarray['userexist'], true); for ($i = 0; $i &lt; $numberOfRows2; $i++) { array_push($fdarray['devices'], $results2[$i]-&gt;devicename); } //end for statement } //end number of rows2 echo json_encode($fdarray); } //end firendsemail == firendsemail } </code></pre> </div>