Need multi project picker

[Garden16_]

I would like to create a custom  field that picks up multiple projects in JIRA. Out of the box JIRA offers only single Project picker. How do I pick up multiple project from my custom fields . Please advice . I am using the following code in script runner for the single project picker 

setFieldByName("Project picker ").convertToMultiSelect([

    ajaxOptions: [

        url           : getBaseUrl() + "https://",

        query         : true,

        formatResponse: "general"

    ]

])

[Nic Brough -Adaptavist-]

This cannot possibly work.

A select list holds a single item.  Converting the UI to a multi-select just makes the data the UI tries to store in the field totally incompatible with it. 

You will need to write an app that can provide your new field type.