Some browsers, such as IE4, IE5, and Opera 7 are not able to accurately obtain the height of a short document loaded after a longer one and cinch up the content below, but all tested browsers except Opera 6 seem to always be able to display the full height of any document loaded into the iframe.
Opera 6 doesn't appear to be able to adjust the height of the iframe. The scrolling attribute in the iframe element can be set to auto to allow op6 and similar browsers the capability of displaying the content with iframe scrollbars.
Unfortunately, in some circumstances that may cause the scrollbars to appear briefly in capable browsers. Another option: set the height of the iframe to accommodate the longest document to be displayed inside it.
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