window.loadResourceCallback

index.html_loadResourceCallback.html

<app>
    <div class="container-fluid">
        <div class="row">
            <div class="col-2"></div>
            <div class="col-8">
                <p></p>
                Loading Blazor WebAssembly...
                <br />
                <div class="progress">
                    <div id="progressbar" class="progress-bar progress-bar-striped active" role="progressbar" style="width:0"></div>
                </div>
            </div>
            <div class="col-2"></div>
        </div>
    </div>
</app>

<script type="text/javascript">
    var i = 0;
    window.loadResourceCallback = (total, name, response) => {
        if (name.endsWith('.dll')) {
            i++;
            const value = parseInt((i * 100.0) / total);
            const pct = value + '%';

            const progressbar = document.getElementById('progressbar');
            progressbar.style.width = pct;
            console.log(i + '/' + total + ' (' + pct + ') ' + name);
        }
    }
</script>