http://java.sun.com/j2se/1.5.0/docs/guide/plugin/developer_guide/using_tags.html
The example shown below is the most commonly used form of the classid attribute. This example instructs Internet Explorer to use the latest installed version of Java Plug-in.
classid="clsid:8AD9C840-044E-11D1-B3E9-00805F499D93"
For example, to use Java Plug-in version 1.5.0, you specify:
classid="clsid:CAFEEFAC-0015-0000-0000-ABCDEFFEDCBA"