Firefox browser plug-in changed to javascript

With the development of web technology, more and more websites use JavaScript to achieve page interaction effects. For ordinary users, they only need to enter the URL and click the button to complete the operation using the browser. However, for some advanced users, they may want to extend the functionality of the web page through browser plug-ins. This article will explain how to change JavaScript through the Firefox browser plug-in.

First of all, we need to understand how the Firefox browser plug-in works. The Firefox browser uses WebExtensions as a plug-in platform. In the plug-in page, JavaScript can be used to interact with the Document Object Model (DOM) to extend browser functions. Plug-ins written in this way can modify the behavior of loaded web pages while the browser is running.

Next, we need to understand the JavaScript language. JavaScript is a scripting language widely used in web pages, with dynamic features, weak type features, object-oriented features, etc. JavaScript usually runs in a browser environment, but its design concepts and implementation methods can be transferred to other environments.

In browsers, JavaScript is usually used to control the interactive behavior of the HTML/CSS interface, including reading and writing local storage, performing operations, etc. For advanced users who want to extend page functionality, they can achieve page interaction effects by writing their own JavaScript scripts. The Firefox plug-in changes elements on the DOM of the web page through JavaScript to extend the page's functionality. The JavaScript code in the plug-in can change static web pages, dynamically added web page elements, and some dynamically changed elements by injecting JavaScript.

Next, we need to write a simple Firefox plug-in to change JavaScript. This page translation plug-in can translate Chinese pages into English.

1. Install the Firefox plug-in development environment

Download the Firefox Developer Edition from the official Firefox plug-in website (https://addons.mozilla.org/) and install its plug-in development tools. This provides a powerful environment for plug-in development.

2. Create a plug-in

Open the WebIDE tool in the installed Firefox Developer Edition and create a new Firefox plug-in project. In this project, a manifest.json file must be included. This file tells the Firefox browser how to run the plug-in.

3. Write JavaScript code

In the new Firefox plug-in project, create a new JavaScript file, which is used to translate the page. For page translation we can use Google Translate API.

In this JavaScript file, we can write the following code to translate the page:

function translatePage() {
    var translateUrl = 'https://translate.googleapis.com/translate_a/single?client=gtx&sl=zh&tl=en&dt=t&q=';
    var translationElements = document.body.querySelectorAll('*');
    Array.from(translationElements).forEach(function(element) {
        if (element.hasChildNodes() && element.textContent.length > 0) {
            var originalText = element.textContent;
            var xhr = new XMLHttpRequest();
            xhr.onreadystatechange = function() {
                if (xhr.readyState == 4 && xhr.status == 200) {
                    var translationResponse = JSON.parse(xhr.responseText);
                    var translatedText = translationResponse[0][0][0];
                    element.textContent = translatedText;
                }
            };
            xhr.open('GET', translateUrl + encodeURIComponent(originalText), true);
            xhr.send();
        }
    });
}

translatePage();

This code will translate all the content on the page into English. After loading the page in the plug-in, the page content is translated, realizing the automatic translation function of the page.

4. Inject JavaScript code

In the Firefox plug-in, injecting JavaScript code can change the DOM elements of the page and expand the page. By adding the scripts attribute to the manifest.json file, you can tell the browser to run the code when the page loads.

Add the following code to the manifest.json file:

"content_scripts": [{
    "matches": ["https://*/*", "http://*/*"],
    "js": ["translate-page.js"]
}]

After adding this code, the Firefox browser will automatically load the translate-page.js file when opening the web page.

So far, we have successfully written a Firefox plug-in and injected a translation script into the plug-in to realize the automatic translation function of the page.

Summary: Through the above learning and practice, we can find that JavaScript writing of Firefox plug-ins is a very important part of plug-in development, and the page can be extended by changing DOM elements. Proficient in JavaScript, DOM and Firefox plug-in development technologies, you can realize more innovative and valuable Firefox extension plug-ins.

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