javascript - 从Greasemonkey到Page的访问变量，反之亦然

我在之前运行的test.js中有以下代码:

alert('stovetop');
alert(greasy);

我在test.user.js中有以下代码:

(function () {

    'use strict';
    var greasy = 'greasy variable';
    document.title = 'greasy title';

}());

'stovetop'收到警报，因此我知道页面javascript可以工作，而document.title得到更改，因此我知道脚本javascript可以工作。但是，在网页上我得到了错误:



如何从网页上访问Greasemonkey设置的变量，反之亦然？

最佳答案

Greasemonkey脚本在单独的范围内运行，并且还可以在沙箱中运行，具体取决于 @grant settings。

此外，问题代码将greasy隔离在函数范围内(如gladoscc所说)。

最后，默认情况下， test.js 将在Greasemonkey脚本执行之前启动，因此无论如何它都不会看到任何设置变量。使用 @run-at document-start 解决该问题。

因此，鉴于此 test.js ，请在</body>之前运行:

window.targetPages_GlobalVar = 'stovetop';

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

然后，以下内容将起作用:

无沙箱:

// ==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);

使用沙箱，无功能范围，unsafeWindow:
==> 重要更新: Greasemonkey changed unsafeWindow handling with version 2.0, the next sample script will not work with GM 2.0 or later。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，无功能范围，脚本注入(inject):

// ==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:

您可以针对this page (output.jsbin.com/esikut/1)测试这些脚本。

如果没有沙箱，则unsafeWindow和window相同。

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

脚本注入(inject)代码将在Firefox之外的各种浏览器中运行。 unsafeWindow当前仅在Firefox + Greasemonkey(或Scriptish)或Chrome + Tampermonkey中有效。

关于javascript - 从Greasemonkey到Page的访问变量，反之亦然，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/13485122/