let fullscreen=false //处于未全屏状态
let element = document.documentElement;
function openFull(){
if (fullscreen) {
if (document.exitFullscreen) {
document.exitFullscreen();
} else if (document.webkitCancelFullScreen) {
document.webkitCancelFullScreen();
} else if (document.mozCancelFullScreen) {
document.mozCancelFullScreen();
} else if (document.msExitFullscreen) {
document.msExitFullscreen();
}
} else {
if (element.requestFullscreen) {
element.requestFullscreen();
} else if (element.webkitRequestFullScreen) {
element.webkitRequestFullScreen();
} else if (element.mozRequestFullScreen) {
element.mozRequestFullScreen();
} else if (element.msRequestFullscreen) {
element.msRequestFullscreen();
}
}
fullscreen = !fullscreen;
}