JQuery UI对话框滚动条未显示在Internet Explorer 8上

I have a modal dialog set on an iframe using JQuery UI showing a separate page. When the page content height is bigger than the dialog height the scrollbars kind of show up in Firefox although a bit far to the right, when I use Internet Explorer 8 or Chrome they do not show tho. My code goes as follows:I have a modal dialog set on an iframe using JQ