One of the feature in Sybase Powerbuilder version 11.5 is a native build the application into the web-based. You don't need to change the scripts, you can migrate directly from window based into web-based. All you need are IIS (Internet Information System) and AJAX installed on the computer, and of course Powerbuilder version 11.5
I'll try explain how to build your window based application into web-based. I'm using the sample application which come with Powerbuilder installer, named: Solutions. It should be on : your documents directory with Sybase\Powerbuilder 11.5\Tutorial as sub directory.