js实现键盘控制DIV移动的方法

本文实例讲述了js实现键盘控制DIV移动的方法。分享给大家供大家参考。具体分析如下：
css样式部分：


代码如下:


<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>


js部分：


代码如下:


<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>


说明：
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
html部分：

代码如下:


被移动的方块【DIV】
<div id="box"></div>


希望本文所述对大家的javascript程序设计有所帮助。


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