如何“您确定要离开此页面吗？ “在浏览器中生成？

I have a page where I open a "modal window". It is really just a DIV, with an IFRAME inside, where I load another page. When I want to refresh the page, the browser pops up a window saying "Are you sure you want to navigate away from this page? Reloading this page will cause the modal window to disappear. Press OK to continue, or Cancel to stay on the current page." I have a page where I open a "modal window". It