Cache problems when I use the showmodaldialog () function of JavaScript to display An ASPX page

When I use the showmodaldialog () function of JavaScript to display An ASPX page, there is a cache problem. The first time I showmodaldialog saw normal content, the content of the page that is viewed for the second time is the content of the first time. That is to say, the page is obtained directly from the cache, rather than from the server. Program This page is never cached forever.
Two solutions:
Method 1: first write an HTM page with an IFRAME embedded in it. The SRC of IFRAME is the ASPX page, and then the showmodaldialog () page is the HTM page instead of the previous ASPX page, in this way, there is no cache problem.
Method 2: write a sentence in page_load () of the ASPX page. Response. expires =-1; This means that the page will expire immediately, so there is no need to nest Htm Page.