function shopCart(ps){
    var p = "";
    if(ps != null){
    if(ps.constructor == String)
        p = "product="+ps;
    else if(ps.constructor == Array)
        p = "product="+ps.join(",");
    }
    if(p != "")
        p += "&";
    p+="t="+(new Date()).getTime();
    ModalDialog.show('/shopcart?'+p,767,100,'我的购物车');
}