如何在没有页边距的情况下全屏显示

body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
}

window.onload = function() {
  document.body.style.width = window.innerWidth + 'px';
  document.body.style.height = window.innerHeight + 'px';
}

var element = document.documentElement;
if (element.requestFullscreen) {
  element.requestFullscreen();
} else if (element.mozRequestFullScreen) {
  element.mozRequestFullScreen();
} else if (element.webkitRequestFullscreen) {
  element.webkitRequestFullscreen();
} else if (element.msRequestFullscreen) {
  element.msRequestFullscreen();
}