从Greasemonkey访问变量到Page，反之亦然

Question

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Answer 1

• Greasemonkey脚本在单独的范围内运行，也可能在沙箱中运行，具体取决于@grant设置。

• 另外，问题代码隔离greasy在功能范围内（如gladoscc所说）。

• 最后，默认情况下， test.js 将在Greasemonkey脚本之前启动，因此无论如何它都不会看到任何设置变量。使用@run-at document-start来解决这个问题。

因此，鉴于此 test.js ，请在运行之前</body>：

window.targetPages_GlobalVar = 'stovetop';

console.log ("On target page, local global: ", targetPages_GlobalVar);
console.log ("On target page, script global: ", gmScripts_GlobalVar);

然后，以下将起作用：

没有沙箱：

// ==UserScript==
// @name        _Greasemonkey and target page, variable interaction
// @include     http://YOUR_SERVER.COM/YOUR_PATH/*
// @include     http://output.jsbin.com/esikut/*
// @run-at      document-start
// @grant       none
// ==/UserScript==

//--- For @grant none, could also use window. instead of unsafeWindow.
unsafeWindow.gmScripts_GlobalVar = 'greasy';

console.log ("In GM script, local global: ", unsafeWindow.targetPages_GlobalVar);
console.log ("In GM script, script global: ", gmScripts_GlobalVar);

window.addEventListener ("DOMContentLoaded", function() {
    console.log ("In GM script, local global, after ready: ", unsafeWindow.targetPages_GlobalVar);
}, false);

使用沙盒，没有函数作用域，unsafeWindow：
==> 重要更新： Greasemonkey更改了unsafeWindow 2.0版本的处理，下一个示例脚本将不适用于GM
2.0或更高版本。其他两个解决方案仍然有效。

// ==UserScript==
// @name        _Greasemonkey and target page, variable interaction
// @include     http://YOUR_SERVER.COM/YOUR_PATH/*
// @include     http://output.jsbin.com/esikut/*
// @run-at      document-start
// @grant    GM_addStyle
// ==/UserScript==
/*- The @grant directive is needed to work around a design change
    introduced in GM 1.0.   It restores the sandbox.
*/

unsafeWindow.gmScripts_GlobalVar = 'greasy';

console.log ("In GM script, local global: ", unsafeWindow.targetPages_GlobalVar);
console.log ("In GM script, script global: ", unsafeWindow.gmScripts_GlobalVar);

window.addEventListener ("DOMContentLoaded", function() {
    console.log ("In GM script, local global, after ready: ", unsafeWindow.targetPages_GlobalVar);
}, false);

使用沙箱，没有函数作用域， 脚本注入 ：

// ==UserScript==
// @name        _Greasemonkey and target page, variable interaction
// @include     http://YOUR_SERVER.COM/YOUR_PATH/*
// @include     http://output.jsbin.com/esikut/*
// @run-at      document-start
// @grant       GM_addStyle
// ==/UserScript==
/*- The @grant directive is needed to work around a design change
    introduced in GM 1.0.   It restores the sandbox.
*/

function GM_main () {
    window.gmScripts_GlobalVar = 'greasy';

    console.log ("In GM script, local global: ", window.targetPages_GlobalVar);
    console.log ("In GM script, script global: ", window.gmScripts_GlobalVar);

    window.addEventListener ("DOMContentLoaded", function() {
        console.log ("In GM script, local global, after ready: ", window.targetPages_GlobalVar);
    }, false);
}

addJS_Node (null, null, GM_main);

function addJS_Node (text, s_URL, funcToRun, runOnLoad) {
    var D                                   = document;
    var scriptNode                          = D.createElement ('script');
    if (runOnLoad) {
        scriptNode.addEventListener ("load", runOnLoad, false);
    }
    scriptNode.type                         = "text/javascript";
    if (text)       scriptNode.textContent  = text;
    if (s_URL)      scriptNode.src          = s_URL;
    if (funcToRun)  scriptNode.textContent  = '(' + funcToRun.toString() + ')()';

    var targ = D.getElementsByTagName ('head')[0] || D.body || D.documentElement;
    targ.appendChild (scriptNode);
}

笔记：

1. 您可以在 此页面 （output.jsbin.com/esikut/1）上测试这些脚本。
2. 由于没有沙箱中，unsafeWindow并且window是相同的。

3. 所有这些脚本在控制台上产生相同的输出：

   In GM script, local global: undefined
   

   In GM script, script global: greasy
   On target page, local global: stovetop
   On target page, script global: greasy
   In GM script, local global, after ready: stovetop

4. 该 脚本注入 代码将在各种除了Firefox浏览器的工作。unsafeWindow目前仅适用于Firefox + Greasemonkey（或Scriptish）或Chrome + Tampermonkey。