ActiveX controls (formerly OLE controls) are reusable components that add functionality to Internet Explorer on Windows only. Macintosh browsers and Netscape Navigator for Windows use Netscape-style plugins to provide similar functionality. Many accessories, including Flash and Shockwave, are available in both forms to support all major browsers.
Whereas prior versions of Internet Explorer for Windows supported both ActiveX controls and Netscape-style plugins, IE5.5 SP2 and IE6.0 do not support Netscape-style plug-ins. They now require ActiveX controls exclusively.
<object> tag is used to insert ActiveX
controls. For Flash and Shockwave objects (which are available as
both ActiveX controls and Netscape-style plugins), Dreamweaver
automatically inserts both the
<embed> tags (the latter is actually
included within the
<object> tag). Browsers
that recognize the
<object> tag, such as
Internet Explorer for Windows, ignore the
<embed> tag; browsers that don’t
<object> tag use the
<embed> tag instead. Therefore, attributes
not specific to one of the tags must be specified redundantly in both
tags. (Example 5-1 demonstrates how attributes are
specified, which differs slightly for each tag.)
attributes are specific to the
classid uniquely identifies an ActiveX
control, which is downloaded from the URL specified by the
codebase attribute if it is not already installed.