diff --git a/site/static/app.js b/site/static/app.js
index 2d17533..02e0a50 100644
--- a/site/static/app.js
+++ b/site/static/app.js
@@ -209,43 +209,27 @@ function uploadFileWS(url, f, idx) {
     ws.binaryType = 'arraybuffer';
 
     ws.onopen = function () {
-      ws.bufferedAmountLowThreshold = CHUNK;
       var reader = new FileReader();
-
-      function sendNext() {
-        var end = Math.min(offset + CHUNK, f.size);
-        reader.readAsArrayBuffer(f.file.slice(offset, end));
-      }
-
       reader.onload = function (e) {
         ws.send(e.target.result);
         offset += CHUNK;
-
-        var pct = Math.round(offset / f.size * 100);
-        if (pct - lastProgress >= 5) {
-          lastProgress = pct;
-          f.progress = pct;
-          renderTable();
-        }
-
-        if (offset >= f.size) {
-          // Когда буфер опустеет — шлём DONE
-          function checkDone() {
-            if (ws.bufferedAmount === 0) {
-              ws.send('DONE');
-            } else {
-              setTimeout(checkDone, 50);
-            }
+        if (offset < f.size) {
+          var pct = Math.round(offset / f.size * 100);
+          if (pct - lastProgress >= 10) {
+            lastProgress = pct;
+            f.progress = pct;
+            renderTable();
           }
-          checkDone();
+          readNext();
+        } else {
+          ws.send('DONE');
         }
       };
-
-      ws.addEventListener('bufferedamountlow', function () {
-        if (offset < f.size) sendNext();
-      });
-
-      sendNext();
+      function readNext() {
+        var end = Math.min(offset + CHUNK, f.size);
+        reader.readAsArrayBuffer(f.file.slice(offset, end));
+      }
+      readNext();
     };
 
     ws.onmessage = function (e) {