This webpage shows how to control the player via Javascript: Start, Stop, Pause, Resume, Resize and FullScreen.

To control the player via Javascript, you can send click events to the player's controls bar buttons, even if the controls bar is hidden and buttons are not visible.
For the player created with "UnrealPlayer1", the ID of Play/Pause button is "UnrealPlayer1_playpause"; the ID of Stop button is "UnrealPlayer1_stop"; the ID of Fullscreen button is "UnrealPlayer1_fullscreen".