神奇简洁的拖动js代码
by joe
at 2009-08-29 11:22:16
original http://xiebiji.com/2009/08/%e7%a5%9e%e5%a5%87%e7%ae%80%e6%b4%81%e7%9a%84%e6%8b%96%e5%8a%a8js%e4%bb%a3%e7%a0%81/
在蓝色论坛发现这个，有点看不懂，研究一下先。
测试地址：code
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>Drag</title>
<style>
* { font-size:12px; font-family:Verdana,宋体; }
html { margin:0px; padding:0px; overflow:auto; }
body { margin:0px; padding:15px; background-color:buttonface; }
#w { position:absolute; width:480px; height:270px; overflow:hidden; border:2px groove #281; cursor:default; -moz-user-select:none; }
#t { line-height:20px; height:20px; width:480px; overflow:hidden; background-color:#27C; color:white; font-weight:bold; border-bottom:1px outset blue; text-align:center; }
#winBody { height:248px; width:480px; overflow-x:hidden; overflow-y:auto; border-top:1px inset blue; padding:10px; text-indent:10px; background-color:white; }
</style>
</head>
<body>
<div id="w">
<div id="t">Demo Win - Drag me</div>
<div id="winBody">Hello world</div>
</div>
</body>
<script>
(function(o,s,x,y,d){
s = o.style;
d = document;
o.onselectstart = function(){ return false; }; //阻止选择
o.onmousedown = function(e){
e = e||event;
x = e.clientX-o.offsetLeft;
y = e.clientY-o.offsetTop;
d.onmousemove = function(e){
e = e||event;
s.left = e.clientX - x + "px";
s.top = e.clientY - y + "px";
}
d.onmouseup = function(){ d.onmouseup = d.onmousemove = ""; }
}
})(document.getElementById("w"))
</script>
</html>把js代码单独拿出来，认真看一下就会发现原理很简单，用”()”把函数括起来然后在后面直接加”(参数)”运行函数。
(function(o,s,x,y,d){ s = o.style;//id为w的元素直接充当这里的o了 d = document;// o.onselectstart = function(){ return false; }; //阻止选择 o.onmousedown = function(e){ e = e||event; x = e.clientX-o.offsetLeft; y = e.clientY-o.offsetTop; d.onmousemove = function(e){ e = e||event; s.left = e.clientX - x + "px"; s.top = e.clientY - y + "px"; } d.onmouseup = function(){ d.onmouseup = d.onmousemove = ""; } } })(document.getElementById("w"))