怎么用javascript进行拖拽
本文译自：http://www.webreference.com/programming/javascript/mk/column2/index.html
所有版权归原文所有
Javascript的特点是dom的处理与网页效果，大多数情况我们只用到了这个语言的最简单的功能，比如制作图片轮播/网页的tab等等，这篇文章将向你展示如何在自己的网页上制作拖拽．
有很多理由让你的网站加入拖拽功能，最简单的一个是数据重组．例如：你有一个序列的内容让用户排序，用户需要给每个条目进行输入或者用select选择，替代前面这个方法的就是拖拽．或许你的网站也需要一个用户可以拖动的导航窗口！那么这些效果都是很简单：因为你可以很容易的实现！
网页上实现拖拽其实也不是很复杂．第一你需要知道鼠标坐标，第二你需要知道用户鼠标点击一个网页元素并实现拖拽，最后我们要实现移动这个元素．
运行代码框
<SCRIPT
src="/upfiles/20060720/drag_drop.js"
type=text/javascript></SCRIPT>
<STYLE type=text/css>LI {
MARGIN-BOTTOM: 10px
}
OL {
MARGIN-TOP: 5px
}
.DragContainer {
BORDER-RIGHT: #669999 2px solid; PADDING-RIGHT: 5px; BORDER-TOP: #669999 2px solid; PADDING-LEFT: 5px; FLOAT: left; PADDING-BOTTOM: 0px; MARGIN: 3px; BORDER-LEFT: #669999 2px solid; WIDTH: 100px; PADDING-TOP: 5px; BORDER-BOTTOM: #669999 2px solid
}
.OverDragContainer {
BORDER-RIGHT: #669999 2px solid; PADDING-RIGHT: 5px; BORDER-TOP: #669999 2px solid; PADDING-LEFT: 5px; FLOAT: left; PADDING-BOTTOM: 0px; MARGIN: 3px; BORDER-LEFT: #669999 2px solid; WIDTH: 100px; PADDING-TOP: 5px; BORDER-BOTTOM: #669999 2px solid
}
.OverDragContainer {
BACKGROUND-COLOR: #eee
}
.DragBox {
BORDER-RIGHT: #000 1px solid; PADDING-RIGHT: 2px; BORDER-TOP: #000 1px solid; PADDING-LEFT: 2px; FONT-SIZE: 10px; MARGIN-BOTTOM: 5px; PADDING-BOTTOM: 2px; BORDER-LEFT: #000 1px solid; WIDTH: 94px; CURSOR: pointer; PADDING-TOP: 2px; BORDER-BOTTOM: #000 1px solid; FONT-FAMILY: verdana, tahoma, arial; BACKGROUND-COLOR: #eee
}
.OverDragBox {
BORDER-RIGHT: #000 1px solid; PADDING-RIGHT: 2px; BORDER-TOP: #000 1px solid; PADDING-LEFT: 2px; FONT-SIZE: 10px; MARGIN-BOTTOM: 5px; PADDING-BOTTOM: 2px; BORDER-LEFT: #000 1px solid; WIDTH: 94px; CURSOR: pointer; PADDING-TOP: 2px; BORDER-BOTTOM: #000 1px solid; FONT-FAMILY: verdana, tahoma, arial; BACKGROUND-COLOR: #eee
}
.DragDragBox {
BORDER-RIGHT: #000 1px solid; PADDING-RIGHT: 2px; BORDER-TOP: #000 1px solid; PADDING-LEFT: 2px; FONT-SIZE: 10px; MARGIN-BOTTOM: 5px; PADDING-BOTTOM: 2px; BORDER-LEFT: #000 1px solid; WIDTH: 94px; CURSOR: pointer; PADDING-TOP: 2px; BORDER-BOTTOM: #000 1px solid; FONT-FAMILY: verdana, tahoma, arial; BACKGROUND-COLOR: #eee
}
.miniDragBox {
BORDER-RIGHT: #000 1px solid; PADDING-RIGHT: 2px; BORDER-TOP: #000 1px solid; PADDING-LEFT: 2px; FONT-SIZE: 10px; MARGIN-BOTTOM: 5px; PADDING-BOTTOM: 2px; BORDER-LEFT: #000 1px solid; WIDTH: 94px; CURSOR: pointer; PADDING-TOP: 2px; BORDER-BOTTOM: #000 1px solid; FONT-FAMILY: verdana, tahoma, arial; BACKGROUND-COLOR: #eee
}
.OverDragBox {
BACKGROUND-COLOR: #ffff99
}
.DragDragBox {
BACKGROUND-COLOR: #ffff99
}
.DragDragBox {
FILTER: alpha(opacity=50); BACKGROUND-COLOR: #ff99cc
}
LEGEND {
FONT-WEIGHT: bold; FONT-SIZE: 12px; COLOR: #666699; FONT-FAMILY: verdana, tahoma, arial
}
FIELDSET {
PADDING-RIGHT: 3px; PADDING-LEFT: 3px; PADDING-BOTTOM: 3px; PADDING-TOP: 3px
}
.History {
FONT-SIZE: 10px; OVERFLOW: auto; WIDTH: 100%; FONT-FAMILY: verdana, tahoma, arial; HEIGHT: 82px
}
#DragContainer8 {
BORDER-RIGHT: #669999 1px solid; PADDING-RIGHT: 0px; BORDER-TOP: #669999 1px solid; PADDING-LEFT: 5px; PADDING-BOTTOM: 0px; BORDER-LEFT: #669999 1px solid; WIDTH: 110px; PADDING-TOP: 5px; BORDER-BOTTOM: #669999 1px solid; HEIGHT: 110px
}
.miniDragBox {
FLOAT: left; MARGIN: 0px 5px 5px 0px; WIDTH: 20px; HEIGHT: 20px
}
PRE {
BORDER-RIGHT: #ccc 1px solid; PADDING-RIGHT: 10px; BORDER-TOP: #ccc 1px solid; PADDING-LEFT: 10px; PADDING-BOTTOM: 10px; BORDER-LEFT: #ccc 1px solid; PADDING-TOP: 10px; BORDER-BOTTOM: #ccc 1px solid; BACKGROUND-COLOR: #f8f8f0
}
</STYLE>
<body>
<FIELDSET id=Demo4><LEGEND>样例- 拖拽页面元素</LEGEND>
<DIV>
<DIV class=DragContainer id=DragContainer4 overclass="OverDragContainer">
<DIV class=DragBox id=Item1 overclass="OverDragBox"
dragclass="DragDragBox">Item #1</DIV>
<DIV class=DragBox id=Item2 overclass="OverDragBox"
dragclass="DragDragBox">Item #2</DIV>
<DIV class=DragBox id=Item3 overclass="OverDragBox"
dragclass="DragDragBox">Item #3</DIV>
<DIV class=DragBox id=Item4 overclass="OverDragBox"
dragclass="DragDragBox">Item #4</DIV></DIV>
<DIV class=DragContainer id=DragContainer5 overclass="OverDragContainer">
<DIV class=DragBox id=Item5 overclass="OverDragBox"
dragclass="DragDragBox">Item #5</DIV>
<DIV class=DragBox id=Item6 overclass="OverDragBox"
dragclass="DragDragBox">Item #6</DIV>
<DIV class=DragBox id=Item7 overclass="OverDragBox"
dragclass="DragDragBox">Item #7</DIV>
<DIV class=DragBox id=Item8 overclass="OverDragBox"
dragclass="DragDragBox">Item #8</DIV></DIV>
<DIV class=DragContainer id=DragContainer6 overclass="OverDragContainer">
<DIV class=DragBox id=Item9 overclass="OverDragBox"
dragclass="DragDragBox">Item #9</DIV>
<DIV class=DragBox id=Item10 overclass="OverDragBox"
dragclass="DragDragBox">Item #10</DIV>
<DIV class=DragBox id=Item11 overclass="OverDragBox"
dragclass="DragDragBox">Item #11</DIV>
<DIV class=DragBox id=Item12 overclass="OverDragBox"
dragclass="DragDragBox">Item #12</DIV></DIV></DIV></FIELDSET>
</body>
</html>
[Ctrl+A 全部选择 提示：你可先修改部分代码，再按运行]
获取鼠标移动信息
第一我们需要获取鼠标的坐标．我们加一个用户函数到document.onmousemove就可以了:
document.onmousemove = mouseMove;
function mouseMove(ev){
ev = ev || window.event;
var mousePos = mouseCoords(ev);
}
function mouseCoords(ev){
if(ev.pageX || ev.pageY){
return {x:ev.pageX, y:ev.pageY};
}
return {
x:ev.clientX + document.body.scrollLeft - document.body.clientLeft,
y:ev.clientY + document.body.scrollTop - document.body.clientTop
};
}
运行代码框
<script>
function mouseMove(ev){
ev = ev || window.event;
var mousePos = mouseCoords(ev);
document.getElementById('xxx').value = mousePos.x;
document.getElementById('yyy').value = mousePos.y;
}
function mouseCoords(ev){
if(ev.pageX || ev.pageY){
return {x:ev.pageX, y:ev.pageY};
}
return {
x:ev.clientX + document.body.scrollLeft - document.body.clientLeft,
y:ev.clientY + document.body.scrollTop - document.body.clientTop
};
}
document.onmousemove = mouseMove;
</script>Mouse X Position:
<input id=xxx type=text>
<br>Mouse Y Position:
<input id=yyy type=text>
</body>
</html>