A way to block rich media (flash) ads from changing CSS elements on a page?

I use display advertising on my site and I noticed certain expandable ads (ads that expand when you roll over them) changes some of the elements on my page by adding the code "visibility: hi开发者_开发问答dden" as inline CSS. This results in text boxes and other content disappearing when the ad loads. Other than simply disabling the offending ad (not a good solution since I never know what other ads might be causing problems or not), is there a way to block ads from injecting CSS instructions into my site like this? Any advice appreciated!

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It's likely the flash add is using the ExternalInterface feature in flash to pipe javascript to your page:

http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/external/ExternalInterface.html

The easiest way to make sure this doesn't happen is to set allowScriptAccess to false on your object tag where the ad is embedded:

http://kb2.adobe.com/cps/164/tn_16494.html

If you need the functionality that require allowScriptAccess (navigateToUrl comes to mind) then things get a little bit more complicated :-)