Disable enter key to submit form

<asp:TextBox ID="txt" runat="server"  onkeydown="return DisableEnter(event);"></asp:TextBox>


function DisableEnter(evt) {
    var charCode = (evt.which) ? evt.which : event.keyCode;
    if (charCode != 13) {
        return true;
    }
    else {
        return false;
    }
}