diff --git a/dart.js b/dart.js
index 67015c1..c95ceb8 100644
--- a/dart.js
+++ b/dart.js
@@ -35,13 +35,14 @@ Drupal.DART.tag = function(tag) {
   tag = typeof(tag) == 'string' ? eval('(' + tag + ')') : tag;
 
   var tagname = tag.settings.options.method == 'adj' ? 'script' : 'iframe';
+  var tagsite = tag.site != null ? '.' + tag.site : '';
   var options = tag.settings.options.method == 'adj' ? 'type="text/javascript"' : 'frameborder="0" scrolling="no" width="' + tag.sz.split("x")[0] + '" height="' + tag.sz.split("x")[1] + '"';;
 
   ad  = '<' + tagname + ' ' + options + ' src="';
   ad += dart_url + "/";
   ad += tag.network_id != "" ? tag.network_id + "/" : "";
   ad += tag.settings.options.method + "/";
-  ad += tag.prefix + '.' + tag.site + "/" + tag.zone + ";";
+  ad += tag.prefix + tagsite + "/" + tag.zone + ";";
   ad += this.keyVals(tag.key_vals);
 
   // Allow other modules to include js that can manipulate each key|val.