H5点击按钮，实现浏览器全屏模式代码

<button class="fullBtn">点击实现全屏</button>

$('.fullBtn').on('click', function() {

         var docElm = document.documentElement;

         // W3C
         if (docElm.requestFullscreen) {
            docElm.requestFullscreen();
         }
         // FireFox
         else if (docElm.mozRequestFullScreen) {
            docElm.mozRequestFullScreen();
         }
         // Chrome等
         else if (docElm.webkitRequestFullScreen) {
            docElm.webkitRequestFullScreen();
         }
         // IE11
         else if (elem.msRequestFullscreen) {
            elem.msRequestFullscreen();
         }
      });