Pixlr API Integration

Pixlr API Integration

I am integrating Pixlr api in one of the website and I am using Pixlr's
express service.
Their sample demo is given at the following link http://developer.pixlr.com/
I am trying to control the Close button by a parameter(exit) which will
redirect to the site .See below
href="javascript:pixlr.overlay.show({image:'http://developer.pixlr.com/_image/example2.jpg',
title:'Example image 2', service:'express', exit: 'http://google.com})
After saving and closing this, it should redirect to google.com.
Unfortunately it is not happening in express service but is working fine
in Editor service. Also, I am not able to understand another parameter
locktarget. Have tried many combinations but not able to use it. Anybody
has worked on Pixlr api and can possibly help ?
Thanks in advance.