JS realizes using keyboard to control DIV up, down, left, right, zoom in and out and change color_layout and layers

Use the keyboard to control DIV. The red square is the keyboard operation area. You can perform the following operations:
Upper: ↑ Lower: ↓ Left: ← Right: →
Ctrl 1: The background turns green
Ctrl 2: The background Turn to yellow
　Ctrl 3: The background turns to blue
　Ctrl ↑: Zoom in
　Ctrl ↓: Zoom out

<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>Control DIV with keyboard</title> <style type="text/css"> html,body{overflow:hidden;} body{margin:0;padding:0;} pre{color:green;padding:10px 15px;background:#f0f0f0;border:1px dotted #333;font:12px/1.5 Courier New;margin:12px;} span{color:#999;} #box{position:absolute;top:50px;left:300px;width:100px;height:100px;background:red;} </style> <pre class="brush:php;toolbar:false"> 红色方块为键盘操作区域，您可以进行如下操作： 上：↑ 下：↓ 左：← 右：→ Ctrl + 1 : 背景变为绿色 Ctrl + 2 : 背景变为黄色 Ctrl + 3 : 背景变为蓝色 Ctrl + ↑ : 放大 Ctrl + ↓ : 缩小 </pre> <div id="box"> </div>
[Ctrl A select all Note: If you need to introduce external Js, you need to refresh to execute

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