Can iframes confuse search engines? They may be able to at least mislead them. Some of the most effective "Black Hat" SEO techniques depend on iframes. Do not rely on any content contained in iframes to be indexed and credited to your page by search engines. This does not, however, mean that you should not use iframes. Unless its purpose is to deceive the search engine, an iframe on your web page should not hurt its search engine performance; it simply may not help.
Can iframes be any size? Yes, even 0 by 0. The dimensions are specified by the width and height attributes. An iframe with dimensions of 0 by 0 (with frameborder set to 0) is referred to as a "hidden" iframe.
Can iframes be located anywhere on the page? Yes, an iframe can be positioned in the same manner as a block level HTML element using CSS and HTML techniques.
What kind of content can an iframe contain? An iframe can contain any kind of page or document that is accessible by a URL and viewable in a web browser, whether it is located on the same site or on a remote site.
If dynamic content on a page that is embedded in an iframe changes, is this change immediately reflected in the iframe contained in the parent page? Yes, when you load another page into an iframe, it isn't an image or snapshot of the other page you are seeing in the iframe; it is the actual page itself. This is a key to the use of iframes for remote scripting, which we will discuss in part two of this article.
Can an iframe resize itself to accommodate dynamic content of varying size? No, the size is fixed. iframes use scrollbars instead. Scrolling is controlled by the scrolling attribute. The options are yes, no, and auto, with the default being auto. If scrolling is disabled, the contained page is truncated at the borders of the iframe. This is a disadvantage of iframes for remote scripting compared to AJAX request-response techniques.
Are iframes supported by all browsers? Yes, all major modern browsers support iframes.
Do iframes have a border? An optional border can be specified by the frameborder attribute. The options are 0 and 1.
Do links contained on a page within an iframe redirect the parent page? No, they redirect the page in the iframe.
Can the page displayed within the iframe change (redirect) as the iframe is being viewed? Yes, the page within the iframe can be redirected to another URL.