# <object> CLASSID



## kkwikness (Jan 25, 2005)

Hi, I'm looking for more information on the classid attribute of the html tag.
I've always noticed these long hex numbers for this attribute but never fully understood what they are.

- What does the hex number actually represent?


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## amanxman (Mar 28, 2006)

Hey

'CLASSID: Defines a class ID value as set in the Windows Registry or a URL"

or a bit more detail:

What is a CLSID?
A Class ID (CLSID) is a 128 bit (large) number that represents a unique id for a software application or application component. Typically they are displayed like this "{AE7AB96B-FF5E-4dce-801E-14DF2C4CD681}".

You can think of a CLSID as a "social security number" for a piece of software, or a software component.

What are they used for?
CLSIDs are used by Windows to identify software components without having to know their "name". They can also be used by software applications to identify a computer, file or other item.

Where do they come from?
Microsoft provides a utility (program) called GUIDGEN.EXE that generates these numbers. They are generated by using the current time, network adapter address (if present) and other items in your computer so that no two numbers will ever be the same.


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## namenotfound (Apr 30, 2005)

ClassID is used mostly by Internet Explorer, and doesn't really need to be included in the tag. A lot of people think you need all this stuff in and thus make theirs bulky, but really can be very slim, only really needing two attributes; "data" and "type".


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