What is "show="?

Just saw this code

[Clark]

A search did not turn up what this code means. In the <option> code I saw somewhere it said show="none" and have no idea what it is.

[BlobFisk]

Hi Clark,

I've never seen this, and according to the W3C [w3.org] it is not a valid attribute of the option tag!

[Clark]

Thanks. I thought I was going crazy :)