Form action attribute, what's the purpose?

Hi,
I've seen this in one of the page, can I remove the action attribute, or do some events occur somewhere? I've read that the form always submit to the page itself, so what's the purpose of the value after the sharp sign (#PurchasedItems)?
Thanks
<form id="Form1" method="post" action="ProductItem.aspx#PurchasedItems" runat="server">
...