iframe 动条显示滚动条


<iframe   src='dd.aspx" id="iframeTotal"  scrolling="no"  style="width:100%; margin-left:1px;border: 1px solid #6d92ad;" frameborder="0"></iframe>
 function setOverHidden(id,height)
        {
            var obj = $("#"+id+"");
            obj.hover(function() {
           // debugger
                if(obj[0].tagName!="IFRAME")
                {
                    if (parseInt(obj.css("height")) >= height) {
                        var _this = $(this);
                        _this.css("height", height).css("overflowY", "scroll");
                    }
                }
                else
                {
                    obj.attr("scrolling","yes");
                }
            }, function() {
                var _this = $(this);
                _this.css("height", height).css("overflowY", "hidden");
            });
        }
我想当鼠标放到iframe上就显示滚动条,但是这样没效果