How To Inject Css Into Webpage Through Chrome Extension

Have you ever found yourself wanting to customize the look of a webpage while browsing with Chrome? Good news! You can easily inject custom CSS into any webpage using a Chrome extension. In this article, we'll take you through the step-by-step process of injecting CSS into a webpage to personalize your browsing experience.

First things first, you'll need to create a Chrome extension to facilitate injecting custom CSS. Follow these simple steps to get started:

1. Create a new folder on your computer and name it something like 'CustomCSSExtension'.
2. Inside the folder, create a manifest file named manifest.json. This file will contain metadata about your extension.
3. Open the manifest.json file with a text editor and add the following code:

{
  "manifest_version": 2,
  "name": "Custom CSS Injector",
  "version": "1.0",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "content_scripts": [
    {
      "matches": [""],
      "js": ["content.js"]
    }
  ]
}

This code snippet sets up the basic structure of your Chrome extension, specifying its name, version, permissions, and content scripts.

4. Next, create a content.js file in the same folder. This file will contain the JavaScript code to inject CSS into webpages. Add the following code to content.js:

chrome.storage.sync.get('customCSS', function(data) {
  if (data.customCSS) {
    const style = document.createElement('style');
    style.textContent = data.customCSS;
    document.head.appendChild(style);
  }
});

5. Now, it's time to add the CSS injection functionality to your extension. Open the popup.js file and add the following code:

document.getElementById('saveButton').addEventListener('click', function() {
  const customCSS = document.getElementById('cssInput').value;
  chrome.storage.sync.set({ customCSS });
});

6. Lastly, create a popup.html file in your extension folder and add the following HTML code:

<title>Custom CSS Popup</title>


  <textarea id="cssInput" rows="10" cols="50"></textarea><br>
  <button id="saveButton">Save CSS</button>

And there you have it! You've now set up the basic structure for your custom CSS Chrome extension. You can now load your extension into Chrome and start injecting custom CSS into webpages.

To inject CSS into a webpage using your extension, simply click on the extension icon in your browser, enter your custom CSS code into the text area, and click the 'Save CSS' button. Refresh the webpage, and voila! Your custom styles should now be applied.

Custom CSS injection through a Chrome extension opens up a world of possibilities for personalizing your browsing experience, tweaking styles, and experimenting with design elements on any webpage. So why wait? Get creative and start customizing your favorite websites today!