关于窗体的移动范围
（以下内容都基于J2SE     1.5）    
我现在有一个普通矩形窗口，我希望能让此窗口只能在一个我设定好的矩形区域内移动。    
 
1.窗口的每条边都不能超出矩形区域的边    
2.在双击该窗口最大化时，该窗口的最大化面积只能是该矩形区域的大小    
3.实现该窗口的透明化（就是说只能看见窗口的边框和顶部的窗口栏，中间部分是矩形区域的内容）    
 
请各位大侠帮忙啊，小弟不胜感激！！

------解决方案--------------------
var x0=0,y0=0,x1=0,y1=0;
var offx=6,offy=6;
var moveable=false;
var hover= 'orange ',normal= 'slategray ';//color;
var index=10000;//z-index;
//开始拖动;
function startDrag(obj)
{
if(event.button==1)
{
//锁定标题栏;
obj.setCapture();
//定义对象;
var win = obj.parentNode;
var sha = win.nextSibling;
//记录鼠标和层位置;
x0 = event.clientX;
y0 = event.clientY;
x1 = parseInt(win.style.left);
y1 = parseInt(win.style.top);
//记录颜色;
normal = obj.style.backgroundColor;
//改变风格;
obj.style.backgroundColor = hover;
win.style.borderColor = hover;
obj.nextSibling.style.color = hover;
sha.style.left = x1 + offx;
sha.style.top = y1 + offy;
moveable = true;
}
}
//拖动;
function drag(obj)
{
if(moveable)
{
var win = obj.parentNode;
var sha = win.nextSibling;
win.style.left = x1 + event.clientX - x0;
win.style.top = y1 + event.clientY - y0;
sha.style.left = parseInt(win.style.left) + offx;
sha.style.top = parseInt(win.style.top) + offy;
}
}
//停止拖动;
function stopDrag(obj)
{
if(moveable)
{
var win = obj.parentNode;
var sha = win.nextSibling;
var msg = obj.nextSibling;
win.style.borderColor = normal;
obj.style.backgroundColor = normal;
msg.style.color = normal;
sha.style.left = obj.parentNode.style.left;
sha.style.top = obj.parentNode.style.top;
obj.releaseCapture();
moveable = false;
}
}

//最小化;
function min(obj)
{
var win = obj.parentNode.parentNode;
var sha = win.nextSibling;
var tit = obj.parentNode;
var msg = tit.nextSibling;
var flg = msg.style.display== "none ";
if(flg)
{
win.style.height = parseInt(msg.style.height) + parseInt(tit.style.height) + 2*2;
sha.style.height = win.style.height;
msg.style.display = "block ";
obj.innerHTML = "0 ";
}
else
{
win.style.height = parseInt(tit.style.height) + 2*2;
sha.style.height = win.style.height;
obj.innerHTML = "2 ";
msg.style.display = "none ";
}
}
//创建一个对象;
function xWin(id,w,h,l,t,tit,msg)
{
index = index+2;
this.id = id;
this.width = w;
this.height = h;
this.left = l;
this.top = t;
this.zIndex = index;
this.title = tit;