FOR LOOP moves to top

Frappe Framework App Development
1

when I use FOR LOOP in coding, when I update, it automatically changes location. Pls help, how to use for loop.

2

Its not clear, please provide details.

https://www.google.co.in/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=for%20loop%20in%20python

https://www.google.co.in/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=for+loop+in+javascript

3
Sr Description Qty Rate Amount
{{ row.idx }} {{ row.item_code }} - {{ row.description }} {{ row.qty }} {{ row.get_formatted("rate", doc) }} {{ row.get_formatted("amount", doc) }}
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Items Tableee.jpg819×512 80.1 KB

Can you please tell me the coding error? Because, if I press update button, FOR Loop will move to top row.