题目：页面中运用iframe嵌入PDF.js的viewer.html时，部份浏览器全屏功用毛病；

题目概况：题目涌现的浏览器主要有：edge（win10自带），火狐（按钮被屏障）；

解决计划：

1.不运用iframe，新标签页翻开；- 摒弃：页面体验不好；

2.不运用iframe，运用模板规划，嵌套页面；- 摒弃：模板与PDF.js款式争执较多，适配后高耦合，不天真；

3.继承运用iframe，坚持原平台作风，重写PDF.js的全屏按钮操纵；- 终究计划：快速有用，低耦合；

全屏代码：

<a href="#" onClick="fullscreenAction()">button</a>
<p id="state" style="display:none;">no</p>

  //行动
  function fullscreenAction() {
      var state = document.getElementById('state').innerText;
      if (state == 'no') {
          fullscreen();
      } else {
          exitFullscreen();
      }
  }
  
  //全屏
  function fullscreen() {
      var docElm = document.documentElement;
      if (docElm.requestFullscreen) {
          docElm.requestFullscreen();
      } else if (docElm.mozRequestFullScreen) {
          docElm.mozRequestFullScreen();
      } else if (docElm.webkitRequestFullScreen) {
          docElm.webkitRequestFullScreen();
      } else if (docElm.msRequestFullscreen) {
          docElm.msRequestFullscreen();
      }
  }

  // 退出全屏
  function exitFullscreen() {
      if (document.exitFullscreen) {
          document.exitFullscreen();
      } else if (document.mozCancelFullScreen) {
          document.mozCancelFullScreen();
      } else if (document.webkitCancelFullScreen) {
          document.webkitCancelFullScreen();
      } else if (document.msExitFullscreen) {
          document.msExitFullscreen();
      }
  }

  // 监听是不是全屏
  window.onload = function() {
      var elem = document.getElementById('state');
      document.addEventListener('fullscreenchange',
          function() {
              elem.innerText = document.fullscreen ? 'yes': 'no';
          },
          false);
      document.addEventListener('mozfullscreenchange',
          function() {
              elem.innerText = document.mozFullScreen ? 'yes': 'no';
          },
          false);
      document.addEventListener('webkitfullscreenchange',
          function() {
              elem.innerText = document.webkitIsFullScreen ? 'yes': 'no';
          },
          false);
      document.addEventListener('msfullscreenchange',
          function() {
              elem.innerText = document.msFullscreenElement ? 'yes': 'no';
          },
          false);
  }