CSP: Move index.html inline code to separate .js file

src/static/js/index.js

@@ -0,0 +1,61 @@
+// @license magnet:?xt=urn:btih:8e4f440f4c65981c5bf93c76d35135ba5064d8b7&dn=apache-2.0.txt Apache-2.0
+/**
+ * Copyright 2011 Peter Martischka, Primary Technology.
+ * Copyright 2020 Richard Hansen
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* global $, customStart */
+
+function randomPadName() {
+  // the number of distinct chars (64) is chosen to ensure that the selection will be uniform when
+  // using the PRNG below
+  const chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-_';
+  // the length of the pad name is chosen to get 120-bit security: log2(64^20) = 120
+  const string_length = 20;
+  // make room for 8-bit integer values that span from 0 to 255.
+  const randomarray = new Uint8Array(string_length);
+  // use browser's PRNG to generate a "unique" sequence
+  const cryptoObj = window.crypto || window.msCrypto; // for IE 11
+  cryptoObj.getRandomValues(randomarray);
+  let randomstring = '';
+  for (let i = 0; i < string_length; i++) {
+    // instead of writing "Math.floor(randomarray[i]/256*64)"
+    // we can save some cycles.
+    const rnum = Math.floor(randomarray[i]/4);
+    randomstring += chars.substring(rnum, rnum + 1);
+  }
+  return randomstring;
+}
+
+$(() => {
+  $('#go2Name').submit(function() {
+    const padname = $('#padname').val();
+    if (padname.length > 0) {
+      window.location = 'p/' + encodeURIComponent(padname.trim());
+    } else {
+      alert('Please enter a name');
+    }
+    return false;
+  });
+
+  $('#button').click(function() {
+    window.location = 'p/' + randomPadName();
+  });
+
+  // start the custom js
+  if (typeof customStart === 'function') customStart();
+});
+
+// @license-end