隨時隨地取得物件座標改良版

function Point (_x, _y) {
this.x = _x;
this.y = _y;
}
function realPosition(_obj) {
var currPos = new Point(_obj.offsetLeft,_obj.offsetTop);
var workPos = new Point(0,0);
if (_obj.offsetParent.tagName.toUpperCase() != "BODY") {
workPos = realPosition(_obj.offsetParent);
currPos.x += workPos.x;
currPos.y += workPos.y;
}
return currPos;
}