how to refresh parent html window using javascript

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Dear sir/s

I have one html window in which, onclick of one button i have open one div.
on that div again i open another html page.i do some entry and close current html page.
but i wont able to refresh my parent html page.
flow as follows

html-1 => Div => html-2

here on close of html-2 i need to refresh html-1 page.

Please help me
Thank you.