JS实现用键盘控制DIV上下左右+放大缩小与变色_布局与层

用键盘控制DIV，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

<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>用键盘控制DIV</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> <script type="text/javascript"> window.onload = function () { var oBox = document.getElementById("box"); var bLeft = bTop = bRight = bBottom = bCtrlKey = false; setInterval(function () { if (bLeft) { oBox.style.left = oBox.offsetLeft - 10 + "px" } else if (bRight) { oBox.style.left = oBox.offsetLeft + 10 + "px" } if (bTop) { oBox.style.top = oBox.offsetTop - 10 + "px" } else if(bBottom) { oBox.style.top = oBox.offsetTop + 10 + "px" } //防止溢出 limit(); },30); document.onkeydown = function (event) { var event = event || window.event; bCtrlKey = event.ctrlKey; switch (event.keyCode) { case 37: bLeft = true; break; case 38: if(bCtrlKey) { var oldWidth = oBox.offsetWidth; var oldHeight = oBox.offsetHeight; oBox.style.width = oBox.offsetWidth * 1.5 + "px"; oBox.style.height = oBox.offsetHeight * 1.5 + "px"; oBox.style.left = oBox.offsetLeft - (oBox.offsetWidth - oldWidth) / 2 + "px"; oBox.style.top = oBox.offsetTop - (oBox.offsetHeight - oldHeight) / 2 + "px"; break; } bTop = true; break; case 39: bRight = true; break; case 40: if(bCtrlKey) { var oldWidth = oBox.offsetWidth; var oldHeight = oBox.offsetHeight; oBox.style.width = oBox.offsetWidth * 0.75 + "px"; oBox.style.height = oBox.offsetHeight * 0.75 + "px"; oBox.style.left = oBox.offsetLeft - (oBox.offsetWidth - oldWidth) / 2 + "px"; oBox.style.top = oBox.offsetTop - (oBox.offsetHeight - oldHeight) / 2 + "px"; break; } bBottom = true; break; case 49: bCtrlKey && (oBox.style.background = "green"); break; case 50: bCtrlKey && (oBox.style.background = "yellow"); break; case 51: bCtrlKey && (oBox.style.background = "blue"); break; } return false }; document.onkeyup = function (event) { switch ((event || window.event).keyCode) { case 37: bLeft = false; break; case 38: bTop = false; break; case 39: bRight = false; break; case 40: bBottom = false; break; } }; //防止溢出 function limit() { var doc = [document.documentElement.clientWidth, document.documentElement.clientHeight] //防止左侧溢出 oBox.offsetLeft <=0 && (oBox.style.left = 0); //防止顶部溢出 oBox.offsetTop <=0 && (oBox.style.top = 0); //防止右侧溢出 doc[0] - oBox.offsetLeft - oBox.offsetWidth <= 0 && (oBox.style.left = doc[0] - oBox.offsetWidth + "px"); //防止底部溢出 doc[1] - oBox.offsetTop - oBox.offsetHeight <= 0 && (oBox.style.top = doc[1] - oBox.offsetHeight + "px") } }; </script> <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 全选 注:如需引入外部Js需刷新才能执行]