使用Ajax和JSP使用Multiselect级联下拉列表

I am sending multiselect dropdown values to a JSP PAGE. Below is the AJAX code that send the multiselect values. The JSP PAge includes SQL query to read from database and show its values in another dropdown. Below code only display cascading dropdown values based on on select and not multiselect. It appears that only one value is sent to apps.jsp and not all values. I tried few changes and it didn't work. Below is the best working code available with me. Any help to get second dropdown display values based on multiselect from first dropdown? Single dropdown works fine with below code. Thank you.I am sending multiselect dropdown values to a J