这个AJAX请求返回＆＃39;成功＆＃39;如果PHP中的输出被复制并粘贴了JSON，但是＆＃39;失败＆＃39;如果它是由文件生成的。看看下面api.php中的评论，看看我的意思。
$.ajax({
url: 'api.php',
dataType: 'JSON',
success: function() {
alert('success');
},
error: function() {
alert('fail');
}
});
api.php：
header('Access-Control-Allow-Origin: *');
$jsonurl = "http://findyourmp.parliament.uk/api/search?q=st+pancras&f=js";
$json = file_get_contents($jsonurl);
// THIS DOESN'T WORK (RETURNS 'FAIL')
print_r($json);
?>
{"results": { "constituencies": [{"constituency_name": "Holborn and St Pancras", "member_name": "Frank Dobson", "member_party": "Labour", "member_biography_url": "http://www.parliament.uk/biographies/commons/Frank-Dobson/180", "member_website": "", "uri": "http://findyourmp.parliament.uk/constituencies/holborn-and-st-pancras.json" } ], "members": [] }}
