getPos

/**
 * 取得对向的大小和坐标 兼容多种浏览器
 * @param {Object} owner
 */
var getPos = function(owner){
        if(owner == undefined){
                return {top : 0, left:0 , width : 0, height : 0};
        }
 
        var e = owner;
        var oTop = e.offsetTop;
        var oLeft = e.offsetLeft;
        var oWidth = e.offsetWidth;
        var oHeight = e.offsetHeight;
        while(e = e.offsetParent)
        {
                oTop += e.offsetTop;
                oLeft += e.offsetLeft;
        }
 
        return {
                top : oTop,
                left : oLeft,
                width : oWidth,
                height : oHeight
        }
}