why does checkbox sojourn checked ff3 nonetheless ie, chrome

so - i have checkbox

<asp:checkbox id="chkorder" runat="server" visible='<%#ischeckboxvisible() %>' 
     checked="false"
     oncheckedchanged="chkorder_checkedchanged" autopostback="true" 
     enableviewstate="false"></asp:checkbox>

the above. now, checkbox gridview databound - rows gridview checkbox set false. problem initial checkbox still loyal checked.

in ie problem doesn't exist, same chrome. i'm controlling out options.
also i

$("checkboxname").attr("checked"); // accurate jquery prepared function.

in ff true; ie false; chrome false.

any tips?

edit

now prepared : generated html - there checked attribute.
the diff between ff ie exactly same.

another thing - grid contains checkboxes an ajax quarrel i page grid, try page 2 - checkedchanged codebehind triggered.