废话不多说，直接上代码
<!DOCTYPE html><html><head lang="en"> <meta charset="UTF-8"> <title></title></head><body><button id="btn">按钮</button><button id="exit">退出</button><script> var btn = document.querySelector("#btn"); var exit = document.querySelector("#exit"); btn.onclick = function () { document.documentElement.webkitRequestFullScreen(); } exit.onclick = function () { if (document.exitFullscreen) { document.exitFullscreen(); } else if (document.mozCancelFullScreen) { document.mozCancelFullScreen(); } else if (document.webkitCancelFullScreen) { document.webkitCancelFullScreen(); } else if (document.msExitFullscreen) { document.msExitFullscreen(); } }</script></body></html>