Hello,

Ok, Let me tried to explain your questions.

1.in http://www.intersoftpt.com/Support/WebGrid/KB/All/#permalink=Hide-a-Column-using-Clientside-Script i saw "WG40"... what is it

The code shows about our WebGrid API. You can find and read it in "Switching to new Client side API".
This API can help you to get the proper object or element without too many codes. We provide more elegant approach to use them.

2.in the webgrid samples, i saw this code

if (SampleManager.IsLiveDemo()) SampleUtility.DisableDataOperation(sender);

Our live sample also has many operations for edit, delete, insert and update. If the database gets modified too many, it would be bad for user experience. User might not see what the original purpose of the sample functionality. This is the function of the code snippet.

Regards,
Handy