How to keep credit card details safe online?

I wouldn't trust any online site with my bank account detailes as you don't know what they are doing with them you should just keep this information to yourself my friend did this and lost everything and couldn't claim it back as it was his own fault for doing it. Please keep your important information to yourself don't be another victim to this and don't keep such information on your system either anybody could get it then clean you out.