HTML & XHTML: The Definitive Guide, 6th Edition

Embedded Content

In this section, we cover three tags that support embedded content. The <object> tag is in the HTML 4 and XHTML standards. It is a generalized hybrid of the deprecated <applet> tag for embedding applets, particularly Java applets, and the <embed> tag extension that lets you include an object whose Multipurpose Internet Mail Extension (MIME) type references the plug-in needed to process and possibly display that object.

The latest standards strongly encourage you to use the <object> tag to incorporate applets and other discrete inclusions in your documents, including images (although the standards do not go so far as to deprecate the <img> tag). Use <object> with the classid attribute to insert Java and other applets into a document, along with their execution parameters as contents of the associated <param> tag. Use <object> with the data attribute to download and display non-HTML/XHTML content, such as multimedia, in the user’s computing environment. Object data may be processed and rendered by an included applet, by utilities that come with your browser, or by a plug-in (helper) application that the user supplies.

For applets, the browser creates a display region in the containing text flow exactly like an inline image or an <iframe>: without line breaks and as a single large entity. The browser then downloads and executes the applet’s program code, if specified, and downloads and renders any included data just after download and display of the document. Execution ...