colour change in form

how to deplay the salary less than 3000 in one colour ,please tell me the where to write code in form

STEPS:

1) Use a for loop on block to identify SAL<3000

2) Use SET_ITEM_PROPERTY('FIELDNAME',FOREGROUND_COLOR,'COLOUR VALUE')

OR

Use SET_ITEM_PROPERTY('FIELDNAME',BACKGROUND_COLOR,'COLOUR VALUE')

OR

create a visual attribute first and
assign it to the FIELD when SAL<3000
by using
SET_ITEM_PROPERTY('FIELDNAME',VISUAL_ATTRIBUTE,'NAME OF VISUAL ATTRIBUTE')