理论上(从我上面链接的页面链接的文章)：

var elem = document.getElementById("myId");  
if (elem.requestFullScreen) {  
  elem.requestFullScreen();  
} else if (elem.mozRequestFullScreen) {  
  elem.mozRequestFullScreen();  
} else if (elem.webkitRequestFullScreen) {  
  elem.webkitRequestFullScreen();  
}