function LoginSubmit(e, loginButtonClientId, loginPanelValidationGroup){
    var keynum;
    
    if(window.event) // IE
    {
        keynum = e.keyCode;
    }
    else if(e.which) // Netscape/Firefox/Opera
    {
        keynum = e.which;
    }
    
    if (keynum)
    {
        if (keynum == 13)
        {
            javascript:WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions(loginButtonClientId, "", true, loginPanelValidationGroup, "", false, true))
        }
    }
    
}