function get_simple_ajax(cmd, target, additional_params){
     var url = 'ajax.php';
     var pars = 'cmd='+cmd+additional_params;
     var myAjax = new Ajax.Updater(target, url, {method: 'get', parameters: pars});
}

function noenter(e) {
    var key;

    if(window.event)
         key = window.event.keyCode;     //IE
    else
         key = e.which;     //firefox
    if(key == 13)
         return false;
    else
         return true;
}