traditionally i would say find a javascript to do it. But if you insist on ASP then the contents of the input must be made into a string. then split into an array (as would be done in javascript)
<%
' Put form contents into a variable
In_String = Request.Form("Input_Name")
' Split the string into an array, separated by a space
WordArray = Split(In_String, " ")
' Count the array rows
Word_Count = UBound(WordArray) + 1
' We must add 1 because arrays are zero based (0, 1, 2 etc)
%>
sorted.