jsonp回调错误 [英] jsonp callback error

问题描述

我使用firefox addon生成器。使用回调未定义运行此代码错误

I'm using firefox addon builder. Running this code errors with "callback is not defined"

function callback(data) {
   window.alert(data.status);
}

$.ajax({
   url: "http://apps.compete.com/sites/google.com/trended/rank/?apikey=210e634a0b3af972daa908a447c735c1&start_date=201112&end_date=201112&jsonp=?",
   dataType: "jsonp",
   jsonp: "jsonp",
   jsonpCallback: "callback"
});

这是api文档： https://www.compete.com/developer/documentation/

推荐答案

我假设你是从内容脚本运行这个。您必须考虑内容脚本并不真正在与网页脚本相同的上下文中运行 - 网页无法查看内容脚本定义的函数，反之亦然（此机制的详细说明）。 JSONP通过在网页中插入< script> 标记来工作。此脚本将在网页的上下文中运行 - 它不会显示您在内容脚本中定义的回调函数。

I'm assuming that you are running this from a content script. You have to consider that content scripts don't really run in the same context as the web page's scripts - the web page cannot see functions defined by content scripts and vice versa (detailed description of this mechanism). JSONP works by inserting a <script> tag into the web page. This script will run in the context of the web page - and it won't see the callback function you defined in the content script.

要定义 callback 函数在窗口上下文中：

To define the callback function in the window context you do:

unsafeWindow.callback = function(data)
{
  window.alert(data.status);
};

但是，您应该使用警告 unsafeWindow 在文档认真和避免它，如果可能的话。使用 request package 在您的扩展中加载数据：

However, you should take the warnings about unsafeWindow in the documentation seriously and avoid it if possible. Use the request package in your extension to load the data:

require("request").Request({
  url: "http://apps.compete.com/sites/google.com/trended/rank/?apikey=210e634a0b3af972daa908a447c735c1&start_date=201112&end_date=201112",
  onComplete: function(response)
  {
    console.log(response.json);
  }
});

然后，您可以将 response.json 您的内容脚本通过一般讯息。

You can then send response.json to your content script via usual messaging.

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