fd.append('f', f);
        var xhr = new XMLHttpRequest();
        xhr.open('POST', '?' + new URLSearchParams({op:'upload', d:curPath}));
        xhr.upload.onprogress = function(e) {
            if (e.lengthComputable) {
                document.getElementById('upbar' + i).style.width = (e.loaded/e.total*100) + '%';
            }
        };
        xhr.onload = function() {
            var d = JSON.parse(xhr.responseText);
            document.getElementById('upst' + i).innerHTML = d.s === 'ok' 
                ? '<span style="color:var(--green)">&#10003; ' + formatSize(d.b) + '</span>'
                : '<span style="color:var(--red)">&#10007; failed</span>';
            if (i === files.length - 1) loadDir(curPath);
        };
        xhr.onerror = function() { document.getElementById('upst' + i).innerHTML = '<span style="color:var(--red)">error</span>'; };
        xhr.send(fd);
    });
}

// Drag & drop
var dz = document.getElementById('dropZone');
dz.addEventListener('dragover', function(e) { e.preventDefault(); dz.classList.add('over'); });
dz.addEventListener('dragleave', function() { dz.classList.remove('over'); });
dz.addEventListener('drop', function(e) { e.preventD