In the following example, a table named mytable is created and a blank record is appended. ISBLANK( ) returns true (.T.) because myfield is blank. A value is placed in myfield, and ISBLANK( ) returns false (.F.) because myfield is no longer blank.
CREATE TABLE mytable FREE (myfield C(20))
APPEND BLANK && Add new blank record
CLEAR
? ISBLANK(myfield) && Displays .T.
REPLACE myfield WITH 'John Smith' && Insert a value in the field
? ISBLANK(myfield) && Displays .F.