working example of saving js state in M4L

I've been trying to work out how to get a JS script to remember some internal state in an M4L device so that innter patch working involving javascript can be, e.g. save in presets etc.

I've had no luck yet. I tried to do an M4L version of the notorious "cowbell" example in the tutorial, using "getvalueof()/setvalueof()" JS functions in a @parameter_enable 1 JS object, but my JS object never seems to recall data with the patcher (i.e. when you call the "howmanycowbells" function, it does not recall a different version for each device.

In the interim I've been working around it by having the javascript object write out the value of getvalueof() to a pattr in parameter mode, and then an initialisation i get the pattr to send that data back again with "setvalueof" prepended.

For your convenience my javascript is included below so that you can inform me how I've been a dunderhead.

comments, critique gratefully accepted.

autowatch = 1;
var numcowbells = 1;

function cowbells(a)
{
    numcowbells = a;
    notifyclients();
}

//AFAICT this is only used for saving JS state with the patcher itself, not in the M4L version
function save()
{
    embedmessage("cowbells", numcowbells);
}

function howmanycowbells()
{
    post("numcowbells", numcowbells);
    outlet(0, numcowbells);
}

function getvalueof() {
    return numcowbells;
}

function setvalueof(a) {
    cowbells(a);
}