if what you meant by "clipboard" is the one under :
System.Windows.Forms.Clipboard
then the usage is like this (usage in C#):
object something = "blabla";
// to set
Clipboard.SetDataObject(something, true);
// to get
string somewhat = Clipboard.GetDataObject().GetData(typeof(string)).ToString();
but in web application, i guess u can't use clipboard... except that you want to use your client's clipboard...
if this is the case, then i guess u should attach an activex on your page to use your client's clipboard.
hope this can help you ^0^