Web-based chat software consists of a web browser enabled client software component and a server software component. The client software can be a browser plug-in, a Java applet, or a plain HTML page. A browser plug-in requires the users to download and install the software prior to participating in a chat. A Java applet is available to the user after it is automatically downloaded by the browser. A plain HTML page chat software system provides a chat client that is an automatically refreshed HTML page delivered to the client computer. This HTML chat software allows embedded HTML tags to be provided by chat users. For example, people can actually type in HTML tags to change the font of their messages to shout or to include pictures or links to other web sites. All web-based client chat software is embedded within an HTML page, which enables the customization of the user interface. The HTML page with the embedded chat client can also display graphics like GIFs and JPEGs and additional logic using Javascript and Java to enhance the functionality of the chat page. This customization is a popular feature for those chat rooms that are advertiser supported with ad banners prominently displayed to all chat users. . > Source