ContentType
These attribute values are content types (also known as media types or MIME types) of a linked or embedded resource. Values of type ContentType give a single content type while values of type ContentTypes give a comma-separated list of content types. Content types are case-insensitive.

Commonly used content types include text/html, image/jpeg, model/vrml, video/quicktime, application/java, text/css, and text/javascript. Many common content types are registered at the IANA.