Connecting to server using HTML5 (Freeze)

Hello! I have an online highscore system to a game I use in my school company's webpage. It works well when I run it on a .exe file but when I export it to the page (HTML5) it just freezes the game when it wants to connect. Does this work with HTML5, and if so, what do I have to do to fix this?

sundecuf.se/spel
(It just freezes when pressing the screen, which will connect it to the server)