2.1.3.4 iframe Handling

Windows Internet Explorer 9 restricts the document mode of webpages that are hosted within iframe elements. If the top-level page is not in IE9 mode, the iframe element cannot render its contents in IE9 mode, even if the web developer specifies it.

This behavior is available only in Internet Explorer 9. The following diagram shows how iframe elements impact the document mode.

Windows Internet Explorer 10 and Internet Explorer 11 both use Quirks Mode emulation if the top-level page is not in EdgeHTML Mode. Quirks Mode in Internet Explorer 10 and Internet Explorer 11 is based on the definition of Quirks Mode from the HTML5 standard.