function getKeyCode(e){
        var characterCode;
        if(e && e.which) {
                e = e
                characterCode = e.which
        } else {
                if (window.event){
                        e = window.event;
                }
                characterCode = e.keyCode
        }
        return characterCode;
}
function checkEnter(e){
        characterCode=getKeyCode(e);
        if(characterCode == 13) {
                return true;
        }
                return false;
}

function keepalive(){
	new Ajax.Request('/keepalive.php', { method: 'post' });
}
setInterval('keepalive()',10000);