gridview edit,update withoust postback

Question

i need to perform gridview edit,update without postback

<EditItemTemplate>
<asp:ImageButton ID="imgbtnUpdate" CommandName="Update" runat="server" ImageUrl="~/images/gupdate.jpg"
ToolTip="Update" Height="20px" Width="20px" />
<asp:ImageButton ID="imgbtnCancel" runat="server" CommandName="Cancel" ImageUrl="~/images/gCancel.jpg"
ToolTip="Cancel" Height="20px" Width="20px" />
</EditItemTemplate>


<ItemTemplate>
<asp:ImageButton ID="imgbtnEdit" CommandName="Edit" runat="server" ImageUrl="~/images/gEdit.jpg"
ToolTip="Edit" Height="20px" Width="20px">

</ItemTemplate>

on clicking edit button in gridview cause postback., i dont want the edit mode to get postbacked... can anyone help on this issue

Thanks