object element's classid attribute ???

[TheBuzzSaw]

I have done a fair amount of research (though maybe not enough). I still have no understanding of the benefits of using this attribute. What do I gain by using it? What do I lose by dropping it?

The last few times I have attempted to use embed code provided by some site, it never really works. I always have to remove that attribute to make it work right.

So, in simple terms: what is classid? And why do I need it?

[Wickham]

The usual method of coding a video a few years ago was to use the object tag with a classid for IE and a nested embed tag for Firefox. The classid varied according to the file type, like .mp4 .mpg .swf and a plugin is downloaded.

You can code for Flash without a classid but the viewer needs Adobe Flash Player already, or he gets a message to install it, which wastes time. This method validates because it doesn't use a nested embed tag (the embed tag doesn't validate) . See item 2 below which uses
<object type="application/x-shockwave-flash"
style="width: 500px; height: 450px; margin: auto;"
id="VideoPlayer" data="yourvideo.swf">
instead of a classid. Most new computers now have Flash Player installed so the classid method is less necessary especially if you think your viewers will have new computers.

See http://www.wickham43.net/flashvideo.php

I'm not an expert in coding video, it's still complicated.