<script?type="text/javascript">
????$("document").ready(function?()?{
????????var?url?=?"server.php";
????????var?data?=?{'inAjax':?1,?'do':?'checkMember',?'username':?'demo'};

????????$.ajax({
????????????url:?url,
????????????type:?'post',
????????????data:?data,
????????????dataType:?'json',
????????????success:?function?(res)?{
????????????????
????????????????//把json字符串轉換為js對象,用來調用數據
//????????????????var?jsonObj?=?JSON.parse(res);
????????????????$("#username").val(res.username);
????????????????$("#groupname").val(res.groupname);
????????????????$("#uid").val(res.uid);

????????????},
????????????error:?function?()?{
????????????????alert('請求異常');
????????????}
????????});
????});
</script>

這樣寫,就可以不用轉換了,都約定為json,直接調用就好

<?php
error_reporting(0);

$inAjax?=?$_POST['inAjax'];
$do?=?$_POST['do'];
$do?=?$do???$do?:?"default";

if?(!$inAjax)
????return?false;

include_once?"db.class.php";

switch?($do)?{
????case?"checkMember":
????????$username?=?$_POST['username'];
????????$sql?=?"SELECT?*?FROM?check_member?WHERE?username='$username'";
????????$result?=?$dbObj->getOne($sql);
????????$resJson?=?json_encode($result);

????????echo?(!empty($result))????$resJson:?"null";
????????break;

????case?"default":
????????die("nothing");
????????break;
}

返回的是個字符串，eval()的作用是將字符串強制轉換成對象