If you have FireFox, shouldn't be a problem, FireFox will warn if a script is posing a risk.
Unfortunately they do not subject Flash media to the same rigors.
Yes, FLash poses more of a risk you your web browser than people actually realise as it is able to perform client side (yyour browser) actions that are not available in regular Javascript.
Fact that you can with creative scripting, produce Flash animations and such in regular javascript, problem being that the programs are rather long. If you could time warp back to the days before Macromedia released Flash, you would soon see what I am talking about.
In a nutshell, Javascript safer than Flash.
How do I know? Well having my browser hijacked by a flash site for one...