How to integrate score API to game sites?

I am able to create a very simple 2D game using the Blueprint Project with basic scoring system. Before I upload the game to Kongregate, I want to upload it to the scoreboard hosted by Kongregate itself.

How do I upload player scores on game sites like Kongregate? Below is the link to their site with details only for Javascript implementation. How do I apply it in a BluePrint Project?

Kongregate Score API

Example of my VERY old game using Stencyl which has the scoring API implemented : Lost Dungeon