jQuery对话框在IE中加载一次，在其他浏览器中加载两次?

I have a jQuery dialog whose content is defined by an iframe. Until the dialog is displayed, the content of this iframe is invisible. In IE, this content and its associated javascript is executing, so that when the dialog is displayed, it is evident that the javascript has already completed all its loading work. But in non-IE browsers like Firefox and Chrome, this iframe is, again, executing its javascript before the dialog is visible, but then apparently I have a jQuery dialog whose content is defined