in an entry, comment, or in your profile
Scripting languages are not permitted on LiveJournal because they can be used to retrieve other users' browser cookies, which can compromise the account security for any user who views the page. Developers have investigated alternate ways of allowing these languages, but haven't found a way to allow "safe" scripts while blocking those that create security risks.
LiveJournal prohibits the direct use of several HTML tags: <iframe>, <embed>, <object>, as well as some attributes of the <div> tag. However, you can use <iframe>, <embed>, <object> when embedding
music, videos, or other active content into an entry, a comment, or your profile.
Please note that the <iframe> tag can only be used in conjunction with sites that are on a site-wide whitelist of approved services. Using the <iframe> tag in conjunction with an unapproved service will result in no content being displayed.
In areas where embedding is disallowed you will need provide a text link
to content you wish to embed rather than including it directly.