An applet is a small application program, usually coded in the Java programming language. An applet can be embedded in an HTML document much like an image or a Flash movie. Here’s an example:
Netscape developed the <applet> tag for this purpose. But the official HTML 4.01 spec deprecates <applet> in favor of the versatile object element.
So the correct method begins with <object type="applet">. The <applet> tag is forbidden in HTML 4.01 Strict but permitted in HTML 4.01 Transitional.
In practice, Java applets are usually still deployed with the <applet> tag to accommodate browsers that still don’t understand <object type="applet">.