(Un)Install event handlers - Provides on() and off() functions. WIP

onoff.js

var eventsmap = [];

function on(elems, evnm, callback) {
        var i, len, uuid;

        if(elems.length == undefined)
                elems = [elems];
        len = elems.length;
        if(!len)
                return;
        for(i = 0; i < len; ++i) {
                if(elems[i].__id == undefined) {
                        uuid = eventsmap.length;
                        elems[i].__id = uuid;
                }
                else
                        uuid = elems[i].__id;
                if(eventsmap[uuid] == undefined)
                        eventsmap[uuid] = {};
                if(eventsmap[uuid][evnm] == undefined) {
                        eventsmap[uuid][evnm] = [];
                        elems[i].addEventListener(evnm, onevent, false);
                }
                eventsmap[uuid][evnm].push(callback);
        }
}

function off(elems, evnm, callback) {
        var uuid, i, ilen, j, jlen;

        if(elems.length == undefined)
                elems = [elems];
        ilen = elems.length;
        if(!ilen)
                return;

        for(i = 0, ilen = elems.length; i < ilen; ++i) {
                uuid = elems[i].__id;
                for(j = 0, jlen = eventsmap[uuid][evnm].length; j < jlen; ++j) {
                        if(!callback || eventsmap[uuid][evnm][j] == callback) {
                                eventsmap[uuid][evnm].splice(j, 1);
                                if(eventsmap[uuid][evnm].length == 0) {
                                        elems[i].removeEventListener(evnm, onevent, false);
                                        delete eventsmap[uuid][evnm];
                                }
                        }
                }
                if(eventsmap[uuid].length == 0)
                        eventsmap.splice(uuid, 1);
        }
}

function onevent(ev) {
        var uuid = this.__id, evnm = ev.type, cbs = eventsmap[uuid][evnm];
        var i, len, r, cbs, rv = null;

        for(i = 0, len = cbs.length; i < len; ++i) {
                r = cbs[i].apply(this, [ev]);
                if(rv == null && r != undefined && !r) {
                        rv = 0;
                        continue;
                }
        }
        if(rv == 0) {
                ev.stopPropagation();
                ev.preventDefault();
        }
}