Frustrated with implementing an iframe code on your site because it keeps disappearing when you save it? WordPress strips iframes because of security concerns, but you can still use an iframe on your WordPress site by entering the code in the HTML editor instead of the visual editor.
To add an iframe code, create a new post or page and click the tab for HTML edit. Paste your iframe code and click publish and you?re all set!
But, if you try to go back and edit that post or page in the Visual editor, you?ll find that editing the post will remove the iframe code. Argh! You?ll need to open it in the HTML editor, and only the HTML editor to keep the code intact.
WordPress decides which editor to use based on which editor you last used when saving a post or a page. It usually defaults to the Visual editor because that?s what most of us use when writing. To get it to open a post in the HTML editor, create a different post draft and save it with the HTML editor open.
Then, open that post or page with iframe code and it will open to the HTML editor, preventing your iframe code from being stripped. Make your edits, then update the post or page without switching over to the Visual editor. Your iframe code will stay intact!
Hope that helps, copied from here:
http://savvyblogging.net/prevent-wor...r-iframe-code/