Syndicated ConditionalChatLink custom_fields

Summary

How can I use the custom_fields that are passed to chat_launch page

Content

I found a lot of posts about this subject but never found how to use the custom_fields that are passed through the url to the chat_launch page.

Is it a PHP value that I can pull using $_GET? Or JavaScript?

Could you please post a code example?

Thank you!

Version

CP 3.7, OSvC 19A

Code Snippet

<script type="text/javascript">
    RightNow.Client.Controller.addComponent(
        {
            container_element_id: "myChatLinkContainer",
            custom_fields: "{\\"ID1\\":\\"VALUE1\\", \\"ID2\\":\\"VALUE2\\"}",
            info_element_id: "myChatLinkInfo",
            link_element_id: "myChatLink",
            instance_id: "sccl_0",
            module: "ConditionalChatLink",