How to make Electron WebView fill specified size?

When building desktop applications with Electron, controlling the size of a WebView is a common requirement. In Electron, WebView is a custom element that can embed external web pages into your application. To make WebView fill a specified size, you can set its width and height via CSS or dynamically adjust its size using JavaScript. Below, I will explain two commonly used methods:

Method 1: Using CSS

You can directly set the width and height of WebView in your CSS file or within a <style> tag. This is the simplest and most direct approach. For example:

css
webview {
  width: 800px;      /* Specified width */
  height: 600px;     /* Specified height */
}

This CSS sets the WebView size to 800x600 pixels. This method is suitable for static layouts but is inflexible as it does not automatically adjust the WebView size when the window size changes.

Method 2: Dynamically Adjusting with JavaScript

If you want WebView to respond to changes in window size, you can use JavaScript to dynamically adjust its size. This is typically done by listening for the window's resize event. Here is an example code:

javascript
const { BrowserWindow } = require('electron');

let mainWindow = new BrowserWindow({ width: 800, height: 600 });
mainWindow.loadURL('file:///path/to/your/html/file.html');

window.addEventListener('resize', function() {
  let webview = document.querySelector('webview');
  if (webview) {
    webview.style.width = window.innerWidth + 'px';
    webview.style.height = window.innerHeight + 'px';
  }
});

In this example, whenever the window size changes, the WebView's width and height are re-set to fill the window.

Practical Example

Suppose you are developing an Electron application that needs to embed an external website, and you want the WebView to automatically adjust as the application window size changes. You can use the JavaScript method described above to achieve this functionality. This way, regardless of how the user adjusts the application window size, the embedded webpage adapts to the new size, providing a better user experience.

Conclusion

Setting the size of WebView can be achieved through simple CSS or more flexible JavaScript. The choice depends on your specific requirements, such as whether you need to respond to window size changes. In actual development, choose the appropriate method based on your application's design requirements.