PARAMETERS: txt_pass TYPE string.
*“txt_pass“是要接收密码的字段，则在选择屏幕的输出事件中加入如下代码，修改这个字段“不可见”：
AT SELECTION-SCREEN OUTPUT. LOOP AT SCREEN. IF screen-name = 'TXT_PASS'. screen-invisible = '1'. MODIFY SCREEN. ENDIF. ENDLOOP.
