如何获取异步JSONP请求的值？

Question

I need to receive a value of JSONP async request. When I assigning "data" to global variable, I receive a empty object. Please, help me.

Now, I my code get

var url = "http://local/main/getEventData/" + event_id;
var script = document.createElement('script');
script.setAttribute('src', url);
document.getElementsByTagName('head')[0].appendChild(script);

var event_data = {};

function callback(data) {
    event_data = data;
}

and JSONP

callback({name: 'John'})

PS Request absolutely works and I can display data variable via console.log(data)

Answer 1

Use the data when you get it, not (as I assume you are trying now) as soon as you're requested it.

function callback(data) {
    event_data = data;
    // Now you have the data, do something with it.
}

// Don't try to use event_data here. There's no way 
// to know if the callback has fired yet

Answer 2

What you've got will work just fine. You'll just have to put the code (or a call to a function, or whatever) inside your "callback" function so that the code doesn't run until the script is retrieved.