Web Design in a Nutshell, 3rd Edition

File (MIME) Types

Servers add a header to each document, which tells the browser the type of file it is sending. The browser determines how to handle the file based on that information—for example, whether to display the contents in the window, or to launch the appropriate plug-in or helper application.

The system for communicating media types closely resembles MIME (Multipurpose Internet Mail Extension) , which was originally developed for sending attachments in email . The server needs to be configured to recognize each MIME type to successfully communicate the media type to the browser.

If you want to deliver media beyond the standard HTML files and graphics (such as a Shockwave Flash movie or an audio file), you should contact your server administrator to be sure the server is configured to support that MIME type. Most common formats are built into current versions of server software, but if the format isn’t there already, the administrator can easily set it up if you provide the necessary information.

The exact syntax for configuring MIME types varies among server software; however, they all require the same basic information: type, subtype, and extension. Types are the most broad categories for files. They include text, image, audio, video, application, and so on. Within each category are a number of subtypes. For instance, the file type image includes the subtypes gif, jpeg, and the like. The extension refers to the file’s suffix, which the server uses to determine the file ...