规定区域的JS拖动显示效果
规定区域的JS拖动展示，运行看下效果你就明白了，在指定区域内显示图像，鼠标可以拖动图像查看，自动感应图像边界，非常不错。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<title>规定区域的JS拖动展示效果</title>
<style>
body{background:#000; }
.box{
width:400px;
height:400px;
border:1px solid #555;
overflow:hidden;
position:relative;
margin:0 auto;
}
.box img{
cursor:move;
position:absolute;
}
</style>
</head>
<body>
<div class="box" id="map">
<img src="images/20071118165814235_2.jpg" alt=""/>
</div>
<script>
function BuleJS(box) {
var _box = document.getElementById(box),el = _box.getElementsByTagName("IMG")[0],
r = el.offsetWidth - _box.offsetWidth,bi = el.offsetHeight - _box.offsetHeight;
function getXY(e) {
return e ? [e.pageX, e.pageY] : [event.clientX, event.clientY]
};
el.onmousedown = function(e) {
var a = getXY(e),b = [el.offsetLeft,el.offsetTop];
this.setCapture ? this.setCapture() : e.preventDefault();
document.onmousemove = function(e) {
var c = getXY(e);
el.style.left = Math.max( - r, Math.min(0, c[0] - a[0] + b[0]));
el.style.top = Math.max( - bi, Math.min(0, c[1] - a[1] + b[1]));
}
};
document.onmouseup = function(e) {
e || el.releaseCapture();
document.onmousemove = null;
}
};
BuleJS('map');
</script>
</body>
</html>