为什么 JavaScript 不显示解析后的 json 数据？
这是 JSON 数据的格式：我通过 getjson 从服务器接收的 [{"options":"smart_exp"},{"options":"user_int"},{"options":"blahblah"}] 。我需要在 json 中附加用户输入。我正在尝试这样做：首先将其转换为 javascript 对象，将其附加用户输入，再次转换为 json 对象&将其发送回服务器以进行数据库更新。我已经使用 eval() 将 json 转换为 javaScript 对象。现在无法操作 javascript 对象。如果我将 javascript 对象转换回 json 对象，它会正确显示从服务器发送的所有数据。
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html><head></head>
<body>
<form name="index">
<p><input type = "text" id = "txt" name = "txt"></input></p>
<p><input type = "button" id = "send" name = "send" value = "send"
onClick="ADDLISTITEM();"></input></p>
<select name="user_spec" id="user_spec" />
</form>
<script>
function ADDLISTITEM()
{// this script suffers from errors on eval/JSON.parse methods
alert (json.length);//outputs corrcet with eval
tring = JSON.stringify(json);//outputs corrcet with eval
alert(jsonString);//outputs corrcet with eval
alert(json.options[0]);//no output
}
</script>
<script src="http://code.jquery.com/jquery-latest.min.js">
</script>
<script src="http://www.json.org/json2.js"></script>
<script>
var json;
$(document).ready(function() {
jQuery .getJSON("http://127.0.0.1/conn_mysql.php", function (jsonData) {
json = eval(jsonData);
//json = JSON.parse(jsonData);/*error if uncomment:"IMPORTANT: Remove this line from
json2.js before deployment"*/
$.each(jsonData, function (i, j) {
document.index.user_spec.options[i] = new Option(j.options);
});});
});
</script>
</body>
</html>
This is format of JSON data: [{"options":"smart_exp"},{"options":"user_int"},{"options":"blahblah"}] that I receive through getjson from server. I need to append json with user input. I am trying to do it in this way: 1st convert it into javascript object, append it with user input, again convert to json object & send it back to server for database update. I have converted json to javaScript object using eval(). Now not able to manipulate javascript object. If I convert javascript object back to json object, it displays correctly all data that was sent from server.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html><head></head>
<body>
<form name="index">
<p><input type = "text" id = "txt" name = "txt"></input></p>
<p><input type = "button" id = "send" name = "send" value = "send"
onClick="ADDLISTITEM();"></input></p>
<select name="user_spec" id="user_spec" />
</form>
<script>
function ADDLISTITEM()
{// this script suffers from errors on eval/JSON.parse methods
alert (json.length);//outputs corrcet with eval
tring = JSON.stringify(json);//outputs corrcet with eval
alert(jsonString);//outputs corrcet with eval
alert(json.options[0]);//no output
}
</script>
<script src="http://code.jquery.com/jquery-latest.min.js">
</script>
<script src="http://www.json.org/json2.js"></script>
<script>
var json;
$(document).ready(function() {
jQuery .getJSON("http://127.0.0.1/conn_mysql.php", function (jsonData) {
json = eval(jsonData);
//json = JSON.parse(jsonData);/*error if uncomment:"IMPORTANT: Remove this line from
json2.js before deployment"*/
$.each(jsonData, function (i, j) {
document.index.user_spec.options[i] = new Option(j.options);
});});
});
</script>
</body>
</html>
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（3）
在 jQuery 中，$.getJSON() 的回调被解析后的 JSON 数据调用；只需使用它即可。
应该为数组中的每个 {"options": "xyzzy"} 对象发出警报。
OP编辑帖子后编辑：
您的编辑澄清了一些事情：如果您违反 同源策略。
基本上（除了例外情况（预检检查等）），您只能通过 AJAX 访问同一域上的 URL。如果您的 HTML 文件是本地提供的静态文件，则无法访问 http://127.0.0.1/；如果您的文件是 http://foo.baz.quux.org/，您不能简单地AJAX 到 http://mordor.baz.quux.org 。
In jQuery, $.getJSON()'s callback gets called with parsed JSON data; just use it.
should give you an alert for every {"options": "xyzzy"} object in the array.
EDIT after OP edited their post:
Your edit clarifies things a little: You won't get any data back -- and it will be completely silent, too, as I found out -- if you violate the same origin policy.
Basically (with exceptions (preflight checks, etc)), you can only access URLs on the exact same domain via AJAX. If your HTML file is a static file served locally, it can not access http://127.0.0.1/; if your file is http://foo.baz.quux.org/, you can't simply AJAX into http://mordor.baz.quux.org .
我认为这里的问题与 eval/parse 等或同源策略没有任何关系。您的 json 是一个对象数组，每个对象都包含一个名为 options 的成员。因此，您不能执行
json.options[0]，而必须执行json[0].options。I don't think the problem here has anything to do with eval/parse etc or the same origin policy. Your json is an array of objects each containing a member named options. Therefore you cannot do
json.options[0], you have to dojson[0].options.