How to make fullscreen view directly (HTML5)

How to make fullscreen directly when I test movie in animate CC ?

I try this script, but it seems doesnt work :

//here's the code

this.on("tick", full.bind(this));

var ancs = 0

function full(e) {
fullscreen()
}

var isInFullScreen = (document.fullscreenElement && document.fullscreenElement !== null) ||
(document.webkitFullscreenElement && document.webkitFullscreenElement !== null) ||
(document.mozFullScreenElement && document.mozFullScreenElement !== null) ||
(document.msFullscreenElement && document.msFullscreenElement !== null);

var docElm = document.documentElement;

function fullscreen() {

if (!isInFullScreen) {
if (docElm.requestFullscreen) {
docElm.requestFullscreen();
} else if (docElm.mozRequestFullScreen) {
docElm.mozRequestFullScreen();
} else if (docElm.webkitRequestFullScreen) {
docElm.webkitRequestFullScreen();
} else if (docElm.msRequestFullscreen) {
docElm.msRequestFullscreen();
}

}
}

//end of code

I need some help, please...