Framesets are used to display two or more webpages as a single webpage. A frameset specifies the webpages to display in each section (frame) of the parent webpage.
Frameset are commonly used to centralise navigation. A menu is displayed in one frame with content pages displayed in another. As a user moves through the website, content webpages are updated but the navigation remains unchanged.
A significant limitation of framed sites is that of bookmarking or ‘Adding to Favourites’. As the frameset URL is that of the initial navigation/content combination, a user may not have bookmarked the content they intended. One means of avoiding this is to create a unique frameset for each navigation/content combination (not recommended from a maintenance perspective).
An i-frame is an inline frame. The frame is treated as though it were an image or table. As the content page acts as its own frameset, the problem of bookmarking a specific navigation/content page is overcome.
This element has been available for IE users since version 3.0 and is now supported by Netscape 6.0 and Opera 5.0.