Smartforms are client independant.
SAP scripts are client independent

To output documents using the programming interface, R/3
application programs makes use of scripts or smart forms. 

By design sap script is a word processing tool which
displays data on the form with the help of text elements
where the logic of those is written in the print program and
Forms were designed to be driven from print program, hence
are often termed as client dependent. Smart forms are client
independent. Bcoz it doesn’t use any text elements. it will
be executed through a function module. When a print program
calls a Smart Form, the form itself takes over to produce
output, without any further direction from print program.  

Steps for creation 

Creation of Script 

Print program will determine the output document, the areas
values, and the frequency of the output. The database access
will be made in the print program which will insert them in
the corresponding fields of the form. Script needs direction
from the print program to print output. 

Scripts uses layout set that describes the layout of the
individual print pages and uses text elements to supply
definable output blocks, which a print program can call.  

Creation of smart form 

Ø       Design the form

Ø       Form Activation which returns Function module

Ø       Application program for data retrieval & calling
Smart form. 

Application program calls the function module, the Smart
Form uses the modules interface (which corresponds to the
form interface) to transfer any table data previously
selected and to print the form according to the form
description. In addition form can have additional data
selections. 

driver program is generated automatically by activating the
smartform

we need to write the driver program .no program is generated
 by activating the script

1}scripts are cliend dendent , smartforms are client 
independent

2}scripts we can maintain 99 main windoes & it can not work 
with out mainwindow

smartforms we can maintain only on mein window & in this v 
can creat with out main window ,

3} v can write coding in scripts

  in smartforms v can write codding

1) Script is Client Dependent.
   Smartforms are Client InDependent.

2) Multiple Page formats are possible in Smartforms.
   Multiple Page formats are notpossible in Scripts.
 
3) We can maintain Background Graphics in Smartforms.

4) Scripts doesnot generate any Functionmodules.
   Smartforms generate  Functionmodules.

5) We can add colours in scripts.
   We cannot add colours in Smartforms.

6) Scripts maintains 99 mainwindows .
   Smartforms maintains only one Main window.