There are two types of online casinos- downloadable and no download casinos. Most of them are, however, a combination of both. No download casinos offer instant-play version which you can play in your web browser without the need to install any additional software on your PC. In most cases, however, you need to have a flash plug-in installed, but it often comes in with almost all web browsers nowadays. Some no download casinos may require Java to play the games, while modern online casinos are experimenting with HTML5 related technologies.
The no download casinos are suitable for casino fans that don’t want to install any casino software on their computers or have a PC with a low memory capacity. Since you don’t have to download anything you are also protected from malware.