为界面添加全屏按钮

index.html

@@ -13,6 +13,10 @@
 </head>
 
 <body>
+    <button id="fullscreen-button" class="fullscreen-btn">
+        <span class="icon"><img src="icon/full.png" width="30px"></span>
+    </button>
+
     <div class="main-layout">
         <!-- 左侧内容 -->
         <div class="left-panel">
@@ -69,6 +73,7 @@
     <script src="javascape/max_width.js"></script>
     <script src="javascape/marked.min.js"></script>
     <script src="javascape/purify.min.js"></script>
+    <script src="javascape/full_button.js"></script>
 
 </body>
 </html>