diff --git a/.gitignore b/.gitignore
index abb79824ca150559cd2c27b63f346649b133544d..813dbb755e55bd230d7e321447418b862e9da259 100644
--- a/.gitignore
+++ b/.gitignore
@@ -271,7 +271,10 @@ pvsbin/
 # Try Why3
 /src/trywhy3/trywhy3.js
 /src/trywhy3/trywhy3.byte
-/src/trywhy3/theories.ml
+/src/trywhy3/index.en.html
+/src/trywhy3/index.fr.html
+/src/trywhy3/ace-builds
+/src/trywhy3/alt-ergo-0.99.1
 
 # jessie3
 /src/jessie/config.log
diff --git a/Makefile.in b/Makefile.in
index 7dc667926fba974213f1d812ff8e77b3150a7e17..6d4e0e4f608bbdf99d52ee296c1019d7b309b0bb 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -1436,6 +1436,14 @@ ALTERGOMODS=util/numbers util/version util/options parsing/why_parser parsing/wh
 TRYWHY3CMO=lib/why3/why3.cma
 # $(addprefix $(ALTERGODIR)/src/, $(addsuffix .cmo,$(ALTERGOMODS)))
 
+trywhy3: src/trywhy3/trywhy3.js src/trywhy3/index.en.html src/trywhy3/index.fr.html
+
+%.fr.html: %.prehtml
+	yamlpp -l fr $< -o $@
+
+%.en.html: %.prehtml
+	yamlpp -l en $< -o $@
+
 src/trywhy3/trywhy3.js: src/trywhy3/trywhy3.byte
 	js_of_ocaml --extern-fs -I . -I src/trywhy3 --file=trywhy3.conf:/ \
 		--file=try_alt_ergo.drv:/ \
diff --git a/src/trywhy3/index.html b/src/trywhy3/index.html
deleted file mode 100644
index b5b8789376f8f2e4b5439212ae9eb263140b80b8..0000000000000000000000000000000000000000
--- a/src/trywhy3/index.html
+++ /dev/null
@@ -1,101 +0,0 @@
-<html xmlns="http://www.w3.org/1999/xhtml"
-      style="font-family:Verdana,Arial,Sans-Serif">
-  <head>
-    <title>Try Why3</title>
-    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
-    <link rel="stylesheet" type="text/css" href="style.css" />
-    <!-- color customisation -->
-    <style>
-      .stdout { color : #bbccff; }
-      .stderr { color : #ffcccc ; }
-      .error {
-      position:absolute;
-      background:rgba(200,100,100,0.5);
-      z-index:40;
-      }
-    </style>
-  </head>
-  <body style="background-color:#ddd">
-    <!--invisible elements for the open file dialog -->
-    <input type="file"  id="file-selector" />
-    <div id="background-shadow">
-      <div id="confirm-dialog" >
-	The content of the current buffer will be lost.<br/>
-	<div style="width:70%; display:inline-block;">
-	  <button class="btn"
-		  onclick="confirmReplace();">Confirm</button>
-	  <button class="btn"
-		  onclick="cancelReplace();">Cancel</button>
-	</div>
-      </div>
-    </div>
-    <!-- the main page -->
-    <h1 style="background-color:#356aa0;color:#fff">Try Why3</h1>
-    <p>Type some  program in the text area below, then select
-      'Prove all' in the Why3 menu to generate proof obligations.</p>
-    <p>Related links
-      <ul>
-        <li>The <a href="http://why3.lri.fr/">Why3 home page</a>
-        <li>The <a href="http://ocsigen.org/js_of_ocaml/">Js_of_ocaml</a>
-          compiler used to produce this page
-      </ul>
-    </p>
-    <div class="menu-bar">
-      <ul>
-	<li><a href="#">File</a>
-	  <ul>
-	    <li><a href="#" onclick="openFile();">Open file…</a></li>
-	    <li><a href="#" onclick="saveFile();">Save file as…</a></li>
-	  </ul>
-	</li>
-	<li><a href="#">Edit</a>
-	  <ul>
-	    <li><a href="#" onclick="editor.undo();">Undo</a></li>
-	    <li><a href="#" onclick="editor.redo();">Redo</a></li>
-	    <li><a href="#" onclick="clearBuffer();">Clear buffer</a></li>
-	  </ul>
-	</li>
-	<li><a href="#">Examples</a>
-	  <ul>
-	    <li><a href="#"><div id="drinkers">Drinker's paradox</div></a></li>
-	    <li><a href="#"><div id="simplearith">Simple Arithmetic</div></a></li>
-	    <li><a href="#"><div id="isqrt">Integral square root</div></a></li>
-	  </ul>
-	</li>
-	<li><a href="#">Why3</a>
-	  <ul>
-	    <li><a href="#" id="run">Run main function</a></li>
-	    <li><a href="#" id="prove">Prove all</a></li>
-	  </ul>
-	</li>
-	<li><a href="#">Preferences</a>
-	  <ul>
-	    <li><a href="#"
-		   onclick="document.getElementById('radio-wide').click();"
-		   >
-		<input id="radio-wide" type="radio" name="view"
-		       value="wide" checked="checked" onchange="widescreenView();"
-		   />Split Vertically</a>
-	    </li>
-	    <li><a href="#"
-		   onclick="document.getElementById('radio-std').click();"
-		   >
-		<input id="radio-std" type="radio" name="view" value="std"
-		       onchange="standardView();"
-		   />Split Horizontally</a></li>
-	  </ul>
-	</li>
-	<li style="float:right;"><a href="#">Help</a></li>
-      </ul>
-    </div>
-    <div id="editor-panel">
-      <div id="editor" title="Editor" tabindex="-1" ></div>
-      <div title="Console" id="console">
-      </div>
-    </div>
-    <script defer="true" src="ace-builds/src-noconflict/ace.js" type="text/javascript" charset="utf-8"></script>
-    <script defer="true" type="text/javascript" src="editor_helper.js" ></script>
-    <script defer="true" type="text/javascript" src="trywhy3.js" ></script>
-  </body>
-
-</html>
diff --git a/src/trywhy3/index.prehtml b/src/trywhy3/index.prehtml
new file mode 100644
index 0000000000000000000000000000000000000000..a1b38011d0f86be821f2869a896eb15b7fb6b7ab
--- /dev/null
+++ b/src/trywhy3/index.prehtml
@@ -0,0 +1,169 @@
+<html xmlns="http://www.w3.org/1999/xhtml"
+      style="font-family:Verdana,Arial,Sans-Serif">
+  <head>
+    <title>
+      <#en>Try Why3</#en><#fr>Essayez Why3</#fr>
+    </title>
+    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+    <link rel="stylesheet" type="text/css" href="style.css" />
+    <!-- color customisation -->
+    <style>
+      .stdout { color : #bbccff; }
+      .stderr { color : #ffcccc ; }
+      .error {
+      position:absolute;
+      background:rgba(200,100,100,0.5);
+      z-index:40;
+      }
+    </style>
+  </head>
+  <body style="background-color:#ddd">
+    <!--invisible elements for the open file dialog -->
+    <input type="file"  id="file-selector" />
+    <div id="background-shadow">
+      <div id="confirm-dialog" >
+	<#en>The content of the current buffer will be lost</#en>
+	<#fr>Le contenu actuel du programme sera perdu</#fr>
+        <br/>
+	<div style="width:70%; display:inline-block;">
+	  <button class="btn"
+		  onclick="confirmReplace();">
+            <#en>Confirm</#en>
+            <#fr>Confirmer</#fr>
+          </button>
+	  <button class="btn"
+		  onclick="cancelReplace();">
+            <#en>Cancel</#en>
+            <#fr>Annuler</#fr>
+          </button>
+	</div>
+      </div>
+    </div>
+    <!-- the main page -->
+      <div align="right">
+        <#fr><a href="index.en.html">English version</a></#fr>
+        <#en><a href="index.fr.html">Version fran&ccedil;aise</a></#en>
+      </div>
+    <h1 style="background-color:#356aa0;color:#fff">
+      <#en>Try Why3</#en><#fr>Essayez Why3</#fr>
+    </h1>
+    <p>
+      <#en>
+        Type some program in the text area below, then select
+        'Prove all' in the Why3 menu to generate proof obligations.
+      </#en>
+      <#fr>
+        Tapez un programme dans la zone de texte ci-dessous, puis
+        s&eacute;lectionnez 'Prouver' dans le menu Why3 pour engendrer
+        les obligations de preuve.
+      </#fr>
+    </p>
+    <p><#en>Related links</#en><#fr>Liens utiles</#fr>
+      <ul>
+        <li><#en>The</#en><#fr>La</#fr>
+          <a href="http://why3.lri.fr/">
+            <#en>Why3 home page</#en>
+            <#fr>page principale de Why3</#fr>
+          </a>
+        <li><#en>The</#en><#fr>Le compilateur</#fr>
+          <a href="http://ocsigen.org/js_of_ocaml/">
+            Js_of_ocaml</a>
+          <#en>compiler used to produce this page</#en>
+          <#fr>utilis&eacute; pour produire cette page</#fr>
+      </ul>
+    </p>
+    <div class="menu-bar">
+      <ul>
+	<li><a href="#"><#en>File</#en><#fr>Fichier</#fr></a>
+	  <ul>
+	    <li><a href="#" onclick="openFile();">
+                <#en>Open</#en><#fr>Ouvrir</#fr>
+            </a></li>
+	    <li><a href="#" onclick="saveFile();">
+                <#en>Save as</#en><#fr>Enregister sous</#fr>
+            </a></li>
+	  </ul>
+	</li>
+	<li><a href="#"><#en>Edit</#en><#fr>Edition</#fr></a>
+	  <ul>
+	    <li><a href="#" onclick="editor.undo();">
+                <#en>Undo</#en><#fr>Annuler</#fr>
+            </a></li>
+	    <li><a href="#" onclick="editor.redo();">
+                <#en>Redo</#en><#fr>R&eacute;tablir</#fr>
+            </a></li>
+	    <li><a href="#" onclick="clearBuffer();">
+                <#en>Clear buffer</#en><#fr>Tout effacer</#fr>
+            </a></li>
+	  </ul>
+	</li>
+	<li><a href="#"><#en>Examples</#en><#fr>Exemples</#fr></a>
+	  <ul>
+	    <li><a href="#"><div id="drinkers">
+                  <#en>Drinker's paradox</#en>
+                  <#fr>Paradoxe des buveurs</#fr>
+            </div></a></li>
+	    <li><a href="#"><div id="simplearith">
+                  <#en>Simple Arithmetic</#en>
+                  <#fr>Arithm&eacute;tique simple</#fr>
+            </div></a></li>
+	    <li><a href="#"><div id="isqrt">
+                  <#en>Integral square root</#en>
+                  <#fr>Racine carr&eacute;e enti&egrave;re</#fr>
+            </div></a></li>
+	  </ul>
+	</li>
+	<li><a href="#">Why3</a>
+	  <ul>
+	    <li><a href="#" id="run">
+                <#en>Run main function</#en>
+                <#fr>Ex&eacute;cuter la fonction main</#fr>
+            </a></li>
+	    <li><a href="#" id="prove">
+                <#en>Prove</#en>
+                <#fr>Prouver</#fr>
+            </a></li>
+	  </ul>
+	</li>
+	<li><a href="#">
+            <#en>Preferences</#en>
+            <#fr>Pr&eacute;f&eacute;rences</#fr>
+          </a>
+	  <ul>
+	    <li><a href="#"
+		   onclick="document.getElementById('radio-wide').click();"
+		   >
+		<input id="radio-wide" type="radio" name="view"
+		       value="wide" checked="checked" onchange="widescreenView();"
+		   />
+                <#en>Split Vertically</#en>
+                <#fr>S&eacute;paration verticale</#fr>
+              </a>
+	    </li>
+	    <li><a href="#"
+		   onclick="document.getElementById('radio-std').click();"
+		   >
+		<input id="radio-std" type="radio" name="view" value="std"
+		       onchange="standardView();"
+		   />
+                <#en>Split Horizontally</#en>
+                <#fr>S&eacute;paration horizontale</#fr>
+            </a></li>
+	  </ul>
+	</li>
+	<li style="float:right;"><a href="#">
+            <#en>Help</#en><#fr>Aide</#fr>
+        </a></li>
+      </ul>
+    </div>
+    <div id="editor-panel">
+      <div id="editor" title="Editor" tabindex="-1" ></div>
+      <div title="Console" id="console">
+      </div>
+    </div>
+    <script defer="true" src="ace-builds/src-noconflict/ace.js" type="text/javascript" charset="utf-8"></script>
+    <script defer="true" type="text/javascript" src="editor_helper.js" ></script>
+    <script defer="true" type="text/javascript" src="trywhy3.js" ></script>
+  </body>
+
+</html>
