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diff --git a/data/extensions/jsr@javascriptrestrictor/wrappingS-HTML5.js b/data/extensions/jsr@javascriptrestrictor/wrappingS-HTML5.js
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+++ b/data/extensions/jsr@javascriptrestrictor/wrappingS-HTML5.js
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+/** \file
+ * \brief This file contains wrappers for HTML Audio and Video elements
+ *
+ * \see https://developer.mozilla.org/en-US/docs/Web/API/HTMLMediaElement/canPlayType
+ *
+ *  \author Copyright (C) 2022  Libor Polcak
+ *
+ *  \license SPDX-License-Identifier: GPL-3.0-or-later
+ */
+//
+//  This program is free software: you can redistribute it and/or modify
+//  it under the terms of the GNU General Public License as published by
+//  the Free Software Foundation, either version 3 of the License, or
+//  (at your option) any later version.
+//
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU General Public License for more details.
+//
+//  You should have received a copy of the GNU General Public License
+//  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+
+/** \file
+ * \ingroup wrappers
+ *
+ * Supported codecs (multimedia media types) can be misued for fingerprinting,
+ * see for example the [FPMon paper](https://fpmon.github.io/fingerprinting-monitor/files/FPMON.pdf).
+ *
+ * JShelter provides two modes of protection:
+ *
+ * 1. Strict approach returns all media types as not supported.
+ * 2. Modifies the output of probably/maybe supported codecs.
+ */
+
+/*
+ * Create private namespace
+ */
+(function() {
+	var wrappers = [
+		{
+			parent_object: "HTMLMediaElement.prototype",
+			parent_object_property: "canPlayType",
+			wrapped_objects: [{
+				original_name: "HTMLMediaElement.prototype.canPlayType",
+				wrapped_name: "origF",
+			}],
+			helping_code: `var approach = args[0];`,
+			wrapping_function_args: "media, ...args",
+			wrapping_function_body: `
+					if ((approach == 2) || (approach == 1)) { 
+						return "";
+					}
+					else {
+						var normalized = media.replace(/\s|\\n|\\t|\\r/g, '');
+						var origVal = origF.call(this, media);
+						if (origVal === "") {
+							return origVal;
+						}
+						else {
+							var medcap_prng = alea(domainHash, "MediaCapabilities.prototype.encodingInfo", normalized);
+							var rnd = medcap_prng.get_bits(1);
+							if (rnd == 0) {
+								return "probably";
+							}
+							else {
+								return "maybe";
+							}
+						}
+					}
+				`,
+		},
+	]
+	add_wrappers(wrappers);
+})()