Program way to get fullscreen in WebGL

Hi guys! I've been trying to figure out the program way so as to get fullscreen in WebGL without any extra mouse/keyboard actions from the client side. Are there any options to reach it? Any of them will be highly appriciate including cheats/tricks/hooks and so on.

Currently i've got the only manual way (by mouse click):

 public void ChangeScreenMode()
     {
         if (!IsFullScreen())
         {
             Screen.SetResolution(Screen.currentResolution.width, Screen.currentResolution.height, true);
         }
         else
         {
             Screen.SetResolution(defScreenWidth, defScreenHeight, false);
         }
 
         isFullScreenNow = !IsFullScreen();
     }