hi,
thank you very much,

but i don't know how i can use it at myform.

can i change code as under

*thisform.text1.value=startdate
*thisform.text2.value=enddate
thisform.text3.value=CalculateDays(thisform.text1.value,thisform.text2.value)


FUNCTION CalculateDays(thisform.text1.value, thisform.text2.value)
  LOCAL cycle, tocycle, testdate, ret_val
  ret_val = 0
  tocycle = enddate-startdate
  FOR cycle = 0 TO tocycle
      testdate = thisform.text1.value+cycle
      IF .NOT. INLIST(DOW(ScanDay,1), 6, 7)  && friday, saturday
         ret_val = ret_val + 1
      ENDIF
  ENDFOR

RETURN ret_val

thanks,