<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>Document</title> </head> <body> <input type="file" id="fileButton"> <script> fileButton.addEventListener('change', evt => { const file = fileButton.files[0] const url = URL.createObjectURL(file) const video = document.createElement('video') video.onloadedmetadata = evt => { // Revoke when you don't need the url any more to release any reference URL.revokeObjectURL(url) console.log(video.videoWidth, video.videoHeight) } video.src = url video.load() // fetches metadata }) </script> </body> </html>