Add support to the embed script for specifying the playback speed

app/views/asciicasts/show.js.erb

@@ -30,11 +30,19 @@
     container.style.overflow = 'hidden';
     container.style.padding = '0';
     insertAfter(scriptTag, container);
-    var params = 'container_width=' + container.offsetWidth;
+
+    var params = '?container_width=' + container.offsetWidth;
+
     var size = scriptTag.getAttribute('data-size');
     if (size) {
       params += '&size=' + size;
     }
-    container.innerHTML = '<iframe src="http://<%= request.host_with_port %>/a/<%= @asciicast.id %>/raw?' + params + '" name="asciicast-iframe-<%= @asciicast.id %>" id="asciicast-iframe-<%= @asciicast.id %>" width="300" height="300" scrolling="no" marginheight="0" marginwidth="0" frameborder="0" style="display: block; float: none; visibility: hidden;" onload="this.style.visibility=\'visible\';"></iframe>';
+
+    var speed = scriptTag.getAttribute('data-speed');
+    if (speed) {
+      params += '&speed=' + speed;
+    }
+
+    container.innerHTML = '<iframe src="http://<%= request.host_with_port %>/a/<%= @asciicast.id %>/raw' + params + '" name="asciicast-iframe-<%= @asciicast.id %>" id="asciicast-iframe-<%= @asciicast.id %>" width="300" height="300" scrolling="no" marginheight="0" marginwidth="0" frameborder="0" style="display: block; float: none; visibility: hidden;" onload="this.style.visibility=\'visible\';"></iframe>';
   }
 })();