Update README.md

Author: weixiyen

Diff for: README.md

@@ -19,7 +19,7 @@ Usage Example
 
 	$('#dropzone').filedrop({
 		fallback_id: 'upload_button',   // an identifier of a standard file input element
-		url: 'upload.php',				// upload handler, handles each file separately
+		url: 'upload.php',				// upload handler, handles each file separately, can also be a function returning a url
 		paramname: 'userfile',			// POST parameter name used on serverside to reference file
 		withCredentials: true,			// make a cross-origin request with cookies
 		data: {