Make JOSM remote control based editing work

app/views/site/_josm.html.erb

@@ -1,6 +0,0 @@
-<div id="map">
-  <% query = "lat=#{@lat || 0}&lon=#{@lon || 0}&zoom=#{@zoom}" %>
-  <iframe src="http://127.0.0.1:8111/load_and_zoom?<%= query %>" width="100%" height="100%">
-    <p><%= t 'site.edit.no_iframe_support' %></p>
-  </iframe>
-</div>

app/views/site/edit.html.erb

@@ -19,7 +19,7 @@
 <%= render :partial => 'sidebar', :locals => { :onopen => "resizeMap();", :onclose => "resizeMap();" } %>
 <%= render :partial => 'search' %>
 
-<%= render :partial => @preferred_editor %>
+<%= render :partial => preferred_editor %>
 
 <script type="text/javascript" defer="defer">
   function resizeContent() {

app/views/site/index.html.erb

@@ -19,6 +19,9 @@
 <div id="map">
 </div>
 
+<iframe id="linkloader" style="display: none">
+</iframe>
+
 <div id="permalink">
   <a href="/" id="permalinkanchor"><%= t 'site.index.permalink' %></a><br/>
   <a href="/" id="shortlinkanchor"><%= t 'site.index.shortlink' %></a>
@@ -267,11 +270,33 @@ end
     resizeMap();
   }
 
+  function josmEditHandler() {
+    var extent = getMapExtent();
+
+    $("linkloader").src = "http://127.0.0.1:8111/load_and_zoom?left=" + extent.left + "&top=" + extent.top + "&right=" + extent.right + "&bottom=" + extent.bottom;
+
+    return false;
+  }
+
+  function installEditHandler() {
+    <% if preferred_editor == "josm" %>
+      $("editanchor").onclick =josmEditHandler;
+
+      <% if params[:action] == "edit" %>
+        josmEditHandler();
+      <% end %>
+    <% end %>
+  }
+
   mapInit();
 
   window.onload = handleResize;
   window.onresize = handleResize;
 
+  Event.observe(window, 'load', installEditHandler);
+  Event.observe(window, 'load', handleResize);
+  Event.observe(window, 'resize', handleResize);
+
   <% if params['action'] == 'export' %>
   <%= remote_function :url => { :controller => 'export', :action => 'start' } %>
   <% end %>