Frames
An HTML document may contain a header and a body or a header and a frameset, but not both. For frames the Frames DTD must be used.
<frameset>…</frameset>
Delimit the frameset. The frames layout is given by comma separated lists in the rows and cols attributes.
<frame>…</frame>
Delimit a single frame, or region, within the frameset. A different document linked with the src attribute appears inside.
<noframes>…</noframes>
Contains a normal <body> element with child elements that will appear in web browsers that don't support frames.
<iframe>…</iframe>
An inline frame inside a normal HTML <body>, which embeds another HTML document. A similar effect can also be achieved using the object element. These approaches differ in some ways.