To download video files directly from a webpage using JavaScript, you can utilize the fetch API to retrieve the video data and create a blob from it. This method allows you to create a link element dynamically, which users can click to initiate the download. Here’s a simple example illustrating this process. First, you would specify the URL of the video file you want to download, then fetch the video data as a blob, and finally create an anchor element to trigger the download:

function downloadVideo(videoUrl) {
    fetch(videoUrl)
        .then(response => response.blob())
        .then(blob => {
            const url = window.URL.createObjectURL(blob);
            const a = document.createElement('a');
            a.style.display = 'none';
            a.href = url;
            a.download = 'video.mp4'; // Specify the desired file name
            document.body.appendChild(a);
            a.click();
            window.URL.revokeObjectURL(url);
            a.remove();
        })
        .catch(error => console.error('Error downloading video:', error));
}

// Usage: Place this function in your script and call it with a button click
// Download Video

When the user clicks the button, the `downloadVideo` function is executed, which fetches the video, creates a blob, and triggers the download. This method abstracts away the need for users to manually right-click and save the file, thus simplifying the process. Always ensure you have the right to download the content from the URL you are using, and consider handling larger files and progress indicators as enhancements in your implementation.