Updating Browser
It is important for you to update your browser when updates become available as this helps to prevent hackers from taking advantage of any vulnerabilities older version may pose. In addition, online transactions that involve sensitive data such as credit card information require that the your browser meet the minimum requirements and support encryption 128-bit SSL sessions.
Cookies
Internet cookies are small pieces of data which are used to help websites identify their users when they visit their site. An example of how a cookie is used is when your username is already filled in the login form.
Cookies are sent via HTTP header when you submit information through a form and stored on your local drive as a text file. Generally, cookies pose a low security risk but you still have the option to control the use of cookies from your browser settings, found under under Tools / Options in Internet Explorer and Mozilla.
Please note: Spyware software make use of cookies so it's to your advantage to install spyware removal software.
JavaScript
JavaScript is a scripting language as the name may already indicate and is separate from Java. JavaScript is used primarily to make web pages dynamic and interactive, for example validating information sent through a form. Most browsers support JavaScript but this feature can be turned off, typically under Tools / Option.
However, if you have JavaScript disabled you will lose many of the website's functions and abilities such as dynamic menus, although a well designed website will accommodate users with JavaScript disabled.
Java Applets
Java applets are small applications that run within a browser that are embedded within a web page as opposed to being stand alone applications. Java applets are typically used when the program is too large to be included in the web page or if the author does not want their code to be visible to others. Java applets can be used to run animation/graphics, chat rooms, calculators and various other tasks. In order to use Java applets you have to install a Java plug-in which can be downloaded from Sun Microsystems [1]