功能很简单，却非常的实用，代码更加的简洁，这里就不多废话了
奉上源码：
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title></title>
<style type="text/css">
*
{
margin: 0px;
padding: 0px;
}
.dragBox
{
width: 400px;
height: 200px;
position: absolute;
top: 40%;
left: 40%;
background: #e8e8e8;
z-index: 8001;
}
.dragBox > div
{
height: 30px;
cursor: move;
background: #00ff21;
position: relative;
}
.ui-mask
{
width: 100%;
height: 100%;
background: #000;
position: absolute;
top: 0px;
z-index: 8000;
opacity: 0.4;
filter: Alpha(opacity=40);
}
</style>
<script src="framework/base/jquery-1.8.3.min.js"></script>
<script type="text/javascript"></script>
<script type="text/javascript">
$(function () {
var mouseOffx = 0;
var mouseOffy = 0;
var isDrag = false;
$(".dragBox div:eq(0)").unbind(".click").on("mousedown", function (ev) {
mouseOffx = ev.clientX - $(".dragBox div:eq(0)").offset().left;
mouseOffy = ev.clientY - $(".dragBox div:eq(0)").offset().top;
isDrag = true;
})
$(document).unbind(".click").on("mousemove", function (ev) {
var mourseX = ev.clientX, mourseY = ev.clientY;
var moveX = 0, moveY = 0;
if (isDrag === true) {
moveX = mourseX - mouseOffx;
moveY = mourseY - mouseOffy;
var maxX = $(window).outerWidth(false) - $(".dragBox").outerWidth(false);
var maxY = $(window).outerHeight(false) - $(".dragBox").outerHeight(false);
moveX = Math.min(maxX, Math.max(0, moveX));
moveY = Math.min(maxY, Math.max(0, moveY));
$(".dragBox").css({ "left": moveX, "top": moveY });
}
});
$(document).unbind(".click").on("mouseup", function () {
isDrag = false;
});
});
</script>
</head>
<body>
test
<div class="ui-mask" id="mask" onselectstart="return false"></div>
<div class="dragBox">
<div>
</div>
</div>
</body>
</html>