web拖动Drag&Drop原理，代码如下：
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<html>
<head>
<title>Page Title</title>
<style>
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.drag {}{
cursor: move;
}
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.box {}{
margin: 0px;
width: 200px;
border: 1px solid #ccc;
}
.box h3.title {}{
margin: 0px;
width: 100%;
background-color: #ccc;
}
.box div.content {}{
margin: 0px;
width: 100%;
text-align: left;
}
</style>
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<script type=”text/javascript”>
//GreatGhoul
//兼容ff, ie
//要拖动的对象的title设置为’dragable’
//拖动点的class设置为’drag’，拖动点必须为可拖动对象的子节点
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var DragableObj = {
handle: null,
dx: 0,
dy: 0,
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init: function(e) {
e = e || event;
this.handle = e.target || e.srcElement;
if (this.handle.className.indexOf(‘drag’) == -1) return;
while (this.handle.tagName != ‘HTML’ && this.handle.title != “dragable”)
{
this.handle = this.handle.parentNode || this.handle.parentElement;
}
if (this.handle.title != ‘dragable’) return;
this.handle.style.position = ‘relative’;
this.dx = parseInt(this.handle.style.left + 0) – e.clientX;
this.dy = parseInt(this.handle.style.top + 0) – e.clientY;
document.onmousemove = DragableObj.drag;
},
drag: function(e) {
e = e || event;
if (this.handle != null) {
this.handle.style.left = (e.clientX + this.dx) + ‘px’;
this.handle.style.top = (e.clientY + this.dy) + ‘px’;
}
},
drop: function(e) {
this.handle = null;
document.onmousemove = null;
}
};
document.onmousedown = DragableObj.init;
document.onmouseup = DragableObj.drop;
document.onselectstart = function(e) {
e = e || event;
eo = e.target || event.srcElement;
if (eo.className.indexOf(‘drag’) != -1) return false;
};
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</script>
</head>
<body>
<br>例１：
<div class=”box” title=”dragable”>
<h3 class=”drag title”>拖动标题</h3>
<div class=”content”>内容</div>
</div>
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<br>例２：
<div class=”drag” title=”dragable”>拖动我</div>
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</body>
</html>
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来源：csdn
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