diff --git a/regexpu/eff.css b/regexpu/eff.css
index 53a98fd..b040f65 100644
--- a/regexpu/eff.css
+++ b/regexpu/eff.css
@@ -67,6 +67,10 @@ code {
 	background: #ffb6c1;
 }
 
+.hide {
+	display: none;
+}
+
 @media (min-width: 42em) {
 
 	html {
diff --git a/regexpu/eff.js b/regexpu/eff.js
index b11a080..d1ddc79 100644
--- a/regexpu/eff.js
+++ b/regexpu/eff.js
@@ -4,6 +4,11 @@
 	var es6 = textareas[0];
 	var es5 = textareas[1];
 	var regexpu = window.regexpu = require('regexpu');
+	var inputs = document.getElementsByTagName('input');
+	var checkboxUnicodePropertyEscapes = inputs[0];
+	var checkboxUseUnicodeFlag = inputs[1];
+	var targetLanguage = document.getElementById('target-language');
+	var divUseUnicodeFlag = document.getElementsByTagName('div')[1];
 	var run = document.getElementById('run');
 	var permalink = document.getElementById('permalink');
 	// https://mathiasbynens.be/notes/localstorage-pattern
@@ -27,11 +32,19 @@
 	}
 
 	function update() {
+		var showUnicodeFlagCheckbox = checkboxUnicodePropertyEscapes.checked;
+		checkboxUseUnicodeFlag.disabled = !showUnicodeFlagCheckbox;
+		var useES6 = showUnicodeFlagCheckbox && checkboxUseUnicodeFlag.checked;
+		targetLanguage.textContent = useES6 ? 'ES6' : 'ES5';
+		divUseUnicodeFlag.classList.toggle('hide', !showUnicodeFlagCheckbox);
 		var value = es6.value;
 		var transpiled;
 		var isError = false;
 		try {
-			transpiled = regexpu.transpileCode(value);
+			transpiled = regexpu.transpileCode(value, {
+				'unicodePropertyEscape': checkboxUnicodePropertyEscapes.checked,
+				'useUnicodeFlag': useES6
+			});
 		} catch (exception) {
 			isError = true;
 		}
@@ -42,7 +55,15 @@
 			es6.className = es5.className = '';
 			es5.value = transpiled;
 		}
-		permalink.hash = encode(value);
+		var params = new URLSearchParams();
+		params.set('input', value);
+		if (checkboxUnicodePropertyEscapes.checked) {
+			params.set('unicodePropertyEscape', '1');
+		}
+		if (showUnicodeFlagCheckbox && checkboxUseUnicodeFlag.checked) {
+			params.set('useUnicodeFlag', '1');
+		}
+		permalink.hash = params.toString();
 		storage && (storage.regexpu = value);
 	};
 
@@ -51,7 +72,7 @@
 		eval(es5.value);
 	};
 
-	es6.oninput = update;
+	es6.oninput = checkboxUnicodePropertyEscapes.onchange = checkboxUseUnicodeFlag.onchange =  update;
 
 	if (storage) {
 		storage.regexpu && (es6.value = storage.regexpu);
@@ -59,7 +80,14 @@
 	}
 
 	window.onhashchange = function() {
-		es6.value = decodeURIComponent(location.hash.slice(1));
+		var params = new URLSearchParams(location.hash.slice(1));
+		checkboxUnicodePropertyEscapes.checked = JSON.parse(
+			params.get('unicodePropertyEscape')
+		);
+		checkboxUseUnicodeFlag.checked = JSON.parse(
+			params.get('useUnicodeFlag')
+		);
+		es6.value = params.get('input');
 		update();
 	};
 
@@ -74,6 +102,6 @@ window._gaq = [['_setAccount', 'UA-6065217-60'], ['_trackPageview']];
 (function(d) {
 	var g = d.createElement('script');
 	var s = d.scripts[0];
-	g.src = '//www.google-analytics.com/ga.js';
+	g.src = 'https://www.google-analytics.com/ga.js';
 	s.parentNode.insertBefore(g, s);
 }(document));
diff --git a/regexpu/index.html b/regexpu/index.html
index e72ca57..4d44b2b 100644
--- a/regexpu/index.html
+++ b/regexpu/index.html
@@ -12,13 +12,17 @@ <h2>ES6:</h2>
 var match = string.match(/foo(.)bar/u);
 console.log(match[1]);
 // → '&#x1D306;'</textarea>
-<h2>Transpiled to ES5: (<a href=#run-code id=run>run code</a>, <a href=#var%20string%20%3D%20%27foo%F0%9D%8C%86bar%27%3B%0Avar%20match%20%3D%20string.match%28%2Ffoo%28.%29bar%2Fu%29%3B%0Aconsole.log%28match%5B1%5D%29%3B%0A%2F%2F%20%E2%86%92%20%27%F0%9D%8C%86%27 id=permalink>permalink</a>)</h2>
+<div><label><input type=checkbox> enable Unicode property escapes (<code>\p{…}</code> and <code>\P{…}</code></label></div>
+<div class=hide><label><input type=checkbox disabled> use ES6 <code>u</code> flag in output</label></div>
+<h2>Transpiled to <span id=target-language>ES5</span>: (<a href=#run-code id=run>run code</a>, <a href="#input=var+string+%3D+%27foo%F0%9D%8C%86bar%27%3B%0Avar+match+%3D+string.match(/foo(.)bar/u)%3B%0Aconsole.log(match%5B1%5D)%3B%0A//+%E2%86%92+%27%F0%9D%8C%86%27" id=permalink>permalink</a>)</h2>
 <textarea readonly>var string = 'foo&#x1D306;bar';
 var match = string.match(/foo((?:[\0-\t\x0B\f\x0E-\u2027\u202A-\uD7FF\uE000-\uFFFF]|[\uD800-\uDBFF][\uDC00-\uDFFF]|[\uD800-\uDBFF](?![\uDC00-\uDFFF])|(?:[^\uD800-\uDBFF]|^)[\uDC00-\uDFFF]))bar/);
 console.log(match[1]);
 // → '&#x1D306;'</textarea>
 <h2>About this tool</h2>
 <p>This tool uses <a href=https://mths.be/regexpu><i>regexpu</i></a> to transpile <a href=https://mathiasbynens.be/notes/es6-unicode-regex>ES6 Unicode regular expressions (with a <code>u</code> flag)</a> to equivalent ES5.
+<p>The <a href="https://github.com/mathiasbynens/regexpu-core/blob/master/property-escapes.md">Unicode property escapes functionality</a> is <a href="https://github.com/mathiasbynens/es-regexp-unicode-property-escapes">based on a proposal</a> and may or may not reflect what eventually gets specified.
 <p id=footer>Made by <a href=https://mathiasbynens.be/>@mathias</a> — <a href=https://github.com/mathiasbynens/mothereff.in/tree/master/regexpu>fork this on GitHub!</a></p>
-<script src=vendor/regexpu-bundle.min.js></script>
+<script src=vendor/regexpu-browser.js></script>
+<script src=vendor/url-search-params.js></script>
 <script src=eff.js></script>