JSFiddle - React, Tailwind, and code Playground

HTML

<head></head>
<body>
<input type="file" id="fileinput" onchange="myFunction()">
</body>

JavaScript

function myFunction(){
        var finput = document.getElementById('fileinput');
        var file = finput.files[0];
        console.log(file.size);
        const hashBuffer = crypto.subtle.digest('SHA-256', file);           // hash the message
        const hashArray = Array.from(new Uint8Array(hashBuffer));                     // convert buffer to byte array
        const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
        console.log(hashHex);
    }