Update alt.js

Author: turquoise-turtle

alt.js

@@ -1,3 +1,9 @@
+if ('serviceWorker' in navigator) {
+  window.addEventListener('load', function() {
+    navigator.serviceWorker.register('/service-worker.js');
+  });
+}
+
 //foreach way
 document.querySelector('#fileElem').addEventListener('change', function() {
 	handleFiles(this.files);
@@ -109,4 +115,4 @@ function drop(e) {
 	var dt = e.dataTransfer;
 	var files = dt.files;
 	handleFiles(files);
-}
+}