Refactor: JS Code

优化代码命名和逻辑，增加可读性，更新为现代 JavaScript 写法，窗口关闭按钮改为事件委托，修复用户模式下的 Bug（无法进行设置）

index.html

@@ -42,7 +42,7 @@
 <window>
     <section class="the-window updated">
         <div class="window-head">
-            <button>×</button>
+            <button data-type="close">×</button>
             <h3>导航更新啦</h3>
         </div>
         <div class="window-body">
@@ -66,7 +66,7 @@ <h3>更新预告：</h3>
     </section>
     <section class="the-window about">
         <div class="window-head">
-            <button>×</button>
+            <button data-type="close">×</button>
             <h3>关于本项目</h3>
         </div>
         <div class="window-body">
@@ -93,7 +93,7 @@ <h3>使用了：</h3>
     </section>
     <section class="the-window setting">
         <div class="window-head">
-            <button>×</button>
+            <button data-type="close">×</button>
             <h3>设置</h3>
         </div>
         <div class="window-body">
@@ -104,7 +104,7 @@ <h3>设置</h3>
                 </label>
                 <label>
                     <span>自定义背景：</span>
-                    <select name="background" data-key="back_method"></select>
+                    <select name="background" data-key="background_type"></select>
                 </label>
                 <label>
                     <span>可选的预设导航项</span>

static/main.css

@@ -288,7 +288,6 @@ window.active{
 .the-window.active{
     display: block;
     animation: fade-small-large .3s forwards;
-
 }
 .the-window.closed{
     animation: fade-large-small .3s forwards;