So, you have found some potentially useful information on a web site. How do you know whether it is reliable or just plain junk. Anyone with a little money, time, and technical know-how can put something on the web. At present, there is no review requirement of any kind for web sites. As a result they do not have a good reputation for reliability.
It is necessary to ALWAYS evaluate any thing you find on the web very carefully.
The same basic criteria that you used for evaluating books and periodical articles apply to the web. You just have to look in different places to find the answers you need.
NOTE: At this point in time, there is no consistency in the way web sites are designed, labeled, or structured. As a result, finding the information you need to evaluate a web site can be like a detective game.