JavaScript 拖拽实现（附注释），最经典简单短小精悍！

效果预览：
实现源代码：

<title>Drag[笑的自然最后修改编辑]</title> <div id="r" style="position:absolute; left:100px; top:100px; background-color:#F00; height:80px; width:80px; cursor: pointer;"></div> <div id="g" style="position:absolute; left:250px; top:100px; background-color:#0F0; height:80px; width:80px; cursor: pointer;"></div> <div id="b" style="position:absolute; left:400px; top:100px; background-color:#00F; height:80px; width:80px; cursor: pointer;"></div> <script type="text/javascript"></script>

[Ctrl+A 全选注: 如需引入外部Js需刷新才能执行]