diff --git a/0.bootstrap.js b/0.bootstrap.js
index da2dc5a..bcb6c53 100644
--- a/0.bootstrap.js
+++ b/0.bootstrap.js
@@ -43,7 +43,7 @@ eval("\"use strict\";\n// Instantiate WebAssembly module\nvar wasmExports = __we
 /***/ (function(module, __webpack_exports__, __webpack_require__) {
 
 "use strict";
-eval("__webpack_require__.r(__webpack_exports__);\n/* harmony import */ var gpx_web_utils__WEBPACK_IMPORTED_MODULE_0__ = __webpack_require__(/*! gpx-web-utils */ \"../pkg/gpx_web_utils.js\");\n\n\nconst inputElement = document.getElementById(\"gpxInput\");\n\ninputElement.addEventListener(\"change\", readFiles, false);\n\nfunction readFiles() {\n  if (inputElement.files.length < 2) { alert(\"open two or more files\"); return; }\n\n  const files = Array.from(inputElement.files);\n  const promises = files.map(f => f.text());\n\n  Promise.all(promises).then(gpxes => {\n    const merged = gpx_web_utils__WEBPACK_IMPORTED_MODULE_0__[\"merge\"](gpxes);\n    writeOutput(merged);\n    inputElement.value = \"\";\n  });\n}\n\nfunction writeOutput(file) {\n    const blob = new Blob([file], {type: \"text/gpx\"});\n    const a = document.createElement(\"a\");\n    a.href = URL.createObjectURL(blob);\n    a.download = \"merged.gpx\";\n    a.click();\n    URL.revokeObjectURL(a.href);\n}\n\n\n//# sourceURL=webpack:///./index.js?");
+eval("__webpack_require__.r(__webpack_exports__);\n/* harmony import */ var gpx_web_utils__WEBPACK_IMPORTED_MODULE_0__ = __webpack_require__(/*! gpx-web-utils */ \"../pkg/gpx_web_utils.js\");\n\n\nconst inputElement = document.getElementById(\"gpxInput\");\nconst loadingElement = document.createElement(\"span\");\n\nloadingElement.innerHTML = \"<strong>processing...</strong>\";\ninputElement.value = \"\";\ninputElement.addEventListener(\"change\", readFiles, false);\n\nfunction readFiles() {\n  if (inputElement.files.length < 2) { alert(\"open two or more files\"); return; }\n\n  inputElement.replaceWith(loadingElement);\n  const files = Array.from(inputElement.files);\n  const promises = files.map(f => f.text());\n\n  Promise.all(promises).then(gpxes => {\n    try {\n      const merged = gpx_web_utils__WEBPACK_IMPORTED_MODULE_0__[\"merge\"](gpxes);\n      writeOutput(merged);\n    } catch {\n      alert(\"there was a problem, please check the console.\");\n    } finally {\n      inputElement.value = \"\";\n      loadingElement.replaceWith(inputElement);\n    }\n  });\n}\n\nfunction writeOutput(file) {\n    const blob = new Blob([file], {type: \"text/gpx\"});\n    const anchorElement = document.createElement(\"a\");\n    anchorElement.href = URL.createObjectURL(blob);\n    anchorElement.download = \"merged.gpx\";\n    anchorElement.click();\n    URL.revokeObjectURL(anchorElement.href);\n}\n\n\n//# sourceURL=webpack:///./index.js?");
 
 /***/ }),
 
diff --git a/index.html b/index.html
index 7a414bf..7ffee01 100644
--- a/index.html
+++ b/index.html
@@ -22,19 +22,23 @@
     <h1>
       <a href="https://gpx.thermokar.st">gpx.thermokar.st</a>
     </h1>
-    <span>
+    <p>
       This client-side tool is for merging
       <a href="https://www.topografix.com/gpx.asp">GPX files</a>.
       Please note, this has only been tested on GPX files produced by
       <a href="https://www.garmin.com">Garmin</a> and
       <a href="https://www.strava.com">Strava</a> - your mileage may vary.
-      Source:
-      <a href="https://github.com/thermokarst/gpx-web-utils">
-        https://github.com/thermokarst/gpx-web-utils</a>
-    </span>
+    </p>
     <form>
-      <input id="gpxInput" type="file" multiple>
+      <input id="gpxInput" type="file" multiple accept="text/gpx,.gpx">
     </form>
+    <hr>
+    <p>
+      <small>
+         <a href="https://github.com/thermokarst/gpx-web-utils">
+          https://github.com/thermokarst/gpx-web-utils</a>
+      </small>
+    </p>
     <script src="./bootstrap.js"></script>
   </body>
 </html>