diff --git a/lib/OpenLayers/Tile/Image/IFrame.js b/lib/OpenLayers/Tile/Image/IFrame.js
index 1a2ca77580..2d17a6b3a3 100644
--- a/lib/OpenLayers/Tile/Image/IFrame.js
+++ b/lib/OpenLayers/Tile/Image/IFrame.js
@@ -210,9 +210,7 @@ OpenLayers.Tile.Image.IFrame = {
         // adding all parameters in layer params as hidden fields to the html
         // form element
         var imageSize = this.layer.getImageSize();
-        var params = OpenLayers.Util.getParameters(
-            this.url.substr(this.layer.url.length)
-        );
+        var params = OpenLayers.Util.getParameters(this.url);
             
         for(var par in params) {
             var field = document.createElement('input');