Multi select dropdown for Wordpress plugin

Looking for a WordPress jQuery professional with very good skills in jQuery I created a plugin for advertisings. Customers can decided to show the ads in different countries. For this I have to get a Multi select dropdown. The target country selection will be including correct saving of the country names data from the modal popup within the jQuery update that is already present. Every field in the modal popup is directly saved into table. The selected countries are saved into a separate table country_table. Plugin: you can use existing jQuery plugins. Experience: As Employer I have done more than 90 projects on Freelancer. See attached document to get a good impression of the project. Milestone: 1 and it will be released after finishing (no other options) Start: today Realization: max 2 days and accepted before 26 October (definitive) Developing: on my server (downloading is forbidden and is checked) Copyrights: me