简而言之:我正在使用Electron实现一个单页网站,并且遇到了jQuery不能在全局范围内访问的常见问题。因此,为了解决这个问题,我在下面使用了快速入门示例来简化了该问题,但我无法理解。
如您所见,我只是将以下代码添加到了main.js
文件的末尾,以检查问题是否得到解决:
$(document).ready(function () {
console.log("hi");
});
这是我的
main.js
文件的完整代码:// main.js
// Modules to control application life and create native browser window
const { app, BrowserWindow } = require("electron");
const path = require("path");
function createWindow() {
// Create the browser window.
const mainWindow = new BrowserWindow({
width: 800,
height: 600,
webPreferences: {
preload: path.join(__dirname, "preload.js"),
nodeIntegration: true,
webSecurity: true,
},
});
// and load the index.html of the app.
mainWindow.loadFile("index.html");
// Open the DevTools.
// mainWindow.webContents.openDevTools()
}
// This method will be called when Electron has finished
// initialization and is ready to create browser windows.
// Some APIs can only be used after this event occurs.
app.whenReady().then(() => {
createWindow();
app.on("activate", function () {
// On macOS it's common to re-create a window in the app when the
// dock icon is clicked and there are no other windows open.
if (BrowserWindow.getAllWindows().length === 0) createWindow();
});
});
// Quit when all windows are closed.
app.on("window-all-closed", function () {
// On macOS it is common for applications and their menu bar
// to stay active until the user quits explicitly with Cmd + Q
if (process.platform !== "darwin") app.quit();
});
// In this file you can include the rest of your app's specific main process
// code. You can also put them in separate files and require them here.
$(document).ready(function () {
console.log("hi");
});
我正在将以下HTML代码加载到我的
BrowserWindow
中:<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<!-- https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP -->
<!--This was added otherwise "window.jQuery = window.$ = require('jquery');" will not be executed-->
<meta http-equiv="Content-Security-Policy" content="default-src *; style-src 'self' http://* 'unsafe-inline'; script-src 'self' http://* 'unsafe-inline' 'unsafe-eval'" />
<title>Hello World!</title>
</head>
<body>
<h1>Hello World!</h1>
We are using Node.js <span id="node-version"></span>,
Chromium <span id="chrome-version"></span>,
and Electron <span id="electron-version"></span>.
<script src="node_modules/jquery/dist/jquery.min.js"></script>
<script>window.jQuery = window.$ = require('jquery');</script>
<script src="./renderer.js"></script>
</body>
</html>
根据Electron文档的建议,以下脚本作为
BrowserWindow
脚本附加到preload
:// Preload.js
// All of the Node.js APIs are available in the preload process.
// It has the same sandbox as a Chrome extension.
window.addEventListener("DOMContentLoaded", () => {
const replaceText = (selector, text) => {
const element = document.getElementById(selector);
if (element) element.innerText = text;
};
for (const type of ["chrome", "node", "electron"]) {
replaceText(`${type}-version`, process.versions[type]);
}
});
最后但并非最不重要的是,这是快速启动项目的
package.json
配置文件:{
"name": "electron-quick-start",
"version": "1.0.0",
"description": "A minimal Electron application",
"main": "main.js",
"scripts": {
"start": "electron ."
},
"repository": "https://github.com/electron/electron-quick-start",
"keywords": [
"Electron",
"quick",
"start",
"tutorial",
"demo"
],
"author": "GitHub",
"license": "CC0-1.0",
"devDependencies": {
"electron": "^9.0.2"
},
"dependencies": {
"jquery": "^3.5.1"
}
}
但是,每次我运行该应用程序时,都会出现以下错误提示:
我的应用程序的Powershell输出中也显示了此错误(我只编辑了完整的目录路径):
App threw an error during load ReferenceError: $ is not defined at Object.<anonymous> (...directory\0masterproject\main.js:48:1) at Module._compile (internal/modules/cjs/loader.js:967:30) at Object.Module._extensions..js (internal/modules/cjs/loader.js:1004:10) at Module.load (internal/modules/cjs/loader.js:815:32) at Module._load (internal/modules/cjs/loader.js:727:14) at Function.Module._load (electron/js2c/asar.js:738:28) at loadApplicationPackage (...directory\0masterproject\node_modules\electron\dist\resources\default_app.asar\main.js:109:16) at Object.<anonymous> (...directory\0masterproject\node_modules\electron\dist\resources\default_app.asar\main.js:155:9) at Module._compile (internal/modules/cjs/loader.js:967:30) at Object.Module._extensions..js (internal/modules/cjs/loader.js:1004:10) PS ...directory\0masterproject> npm start
但是,当我关闭此窗口并检查
BrowserWindow
的控制台时,我没有看到任何错误,但是也没有“hi”输出。在遇到此问题之前,我曾遇到未定义
require ()
的问题,已通过添加解决了该问题<script src="node_modules/jquery/dist/jquery.min.js"></script>
在我的jQuery代码之前:
<script>window.jQuery = window.$ = require('jquery');</script>
我在this article中找到了这个解决方案;我已经尝试过this example in Electron's documentation,但无济于事。
请让我知道缺少任何信息。
最佳答案
您混淆了main and renderer processes。使用Electron,负责您的UI的所有代码(即,附加到BrowserWindow
中加载的HTML的JavaScript)都在渲染器进程中运行,而所有其他代码(例如,负责打开窗口或设置app
)都可以运行在主要过程中运行。
在这个主要过程中,您不能使用特定于DOM的全局变量,因为主要过程是纯粹的Node.js。您想使用jQuery做什么,即
$(document).ready(function () {
console.log("hi");
});
尽管如此,仍然无法正常工作,因为在主进程中未定义
document
。另外,主进程的环境与渲染器进程是分开的(这就是为什么必须使用IPC在它们之间进行通信的原因),因此$
中未定义main.js
,因为您是在渲染器HTML中定义的。如果您将以下内容放在HTML文件的末尾(甚至将
renderer.js
包括在HTML的末尾)放在文件的末尾,则可能会得到想要的结果:<script src="node_modules/jquery/dist/jquery.min.js"></script>
<script>
window.jQuery = window.$ = require('jquery');
const $ = window.jQuery;
$(document).ready(function () {
console.log("hi");
});
</script>
<script src="./renderer.js"></script>
毕竟,我建议您通过阅读Electron的文档(例如this article)来熟悉Electron的体系结构,因为当不熟悉main/renderer设计原理时,没有太多会出错的问题,只需简单地解决即可了解此设计。
关于javascript - Electron 弹出窗口(未定义$);控制台日志中没有错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/62204274/