同步GM_xmlhttpRequest异步执行吗? [英] Synchronous GM_xmlhttpRequest acting asynchronously?

问题描述

我正在尝试获取GM_xmlhttpRequest调用以使其行为同步，但是我无法使其按预期运行:

I'm trying to get a GM_xmlhttpRequest call to behave synchronously, but I can't get it to work like I expect:

function myFunction (arg) {
    var a;

    GM_xmlhttpRequest ( {
        method:         "GET",
        url:            "http://example.com/sample/url",
        synchronous:    true,

        onload: function (details) {
            a = details.responseText;
        }
    } );

    return a;
}
b = myFunction ();
alert (b);

在这里，我从没拿到b的任何东西；它是未定义的.我在这里缺少一些步骤吗?
我正在使用Greasemonkey的v0.9.13和Firefox的v9.0.1.

I never get anything back for b here; it's undefined. Is there some step that I'm missing here?
I'm using v0.9.13 of Greasemonkey, and v9.0.1 of Firefox.

推荐答案

在Google中偶然发现了这个主题.

Just stumbled upon this topic in Google.

同步GM_xmlhttpRequest返回结果，而不是在onload-callback中执行它.

Synchronous GM_xmlhttpRequest RETURN the result instead of executing it in the onload-callback.

所以这是正确的:

var details = GM_xmlhttpRequest({
  method:"GET",
  url:"http://site.com/sample/url",
  synchronous: true
});
a = details.responseText;

您在开头创建了变量"a"，切勿填充并返回它.因此，它是未定义的.

You create the var "a" in the beginning, never fill it and return it. Therefore, it is undefined.

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