diff --git a/index.js b/index.js
index a304e0f..29d8a7e 100644
--- a/index.js
+++ b/index.js
@@ -20,7 +20,7 @@ function Screenshot(url, opts) {
   this.format('png');
 
   Object.keys(opts || {}).forEach(function (key) {
-    this[key](opts[key]);
+    if (typeof this[key] == 'function') this[key](opts[key]);
   }.bind(this));
 }
 
diff --git a/test.js b/test.js
index fd8a830..78596dc 100644
--- a/test.js
+++ b/test.js
@@ -35,12 +35,14 @@ var server = http.createServer(function(req, res) {
       width: 1024,
       height: 768,
       timeout: 100,
-      format: 'jpeg'  
+      format: 'jpeg',
+      url: 'trololo'
     });
     t.equal(s._width, 1024);
     t.equal(s._height, 768);
     t.equal(s._timeout, 100);
     t.equal(s._format, 'JPG');
+    t.equal(s.url, url);
     t.end();
   });