What are the different functions used in sap script? What are the parameters used in each Function?

There are three different functions used in SAP Script:
1) OPEN_FORM
2) WRITE_FORM
3) CLOSE_FORM
Parameters in Each Function:
1) OPEN_FORM–
Exporting
Form
Language
2) WRITE_FORM–
Exporting
Element
Window
3) CLOSE_FORM