Difference between ATNEW and ONCHANGE OF in SAP ABAP.

What is the difference between ATNEW and ONCHANGE OF?

Difference between ATNEW and ONCHANGE OF.

AT NEW	ON CHANGE OF
1. They must be used within the loop statements.	1. It can be used within the loop statement & outside of the loop statements also
2. It considers preceding fields also	2. It doesn't consider
3. It can’t be used on more than one field using the SET operator ‘OR’	3. It can be used on the multiple fields using the SET operator ‘OR’
4. The work area is impacted by replacing with Asterisk (*******)marks	4. It doesn’t impact the Work Area