Applets are small programs that can be embedded in an application or HTML page. Unlike applications, applets cannot be executed directly from the operating system and they are restricted (for security reasons) from accessing certain resources on the local computer (such as files). Most web browsers have Java Virtual Machines (JVM) built in and hence are able to run java applets that are embedded in web pages. Although applets are cross-platform compatible and secure they are not widely used in web sites. This is because there can be a small (annoying) delay while the browser starts the JVM and also many users disable java applets from running in their browsers due to security concerns.