Переход к следующему элементу в большом массиве.

var o = {};
o[12344]=somveValue

return o[12344];

(function () {
    var getKeys = ('keys' in Object.prototype) ? Object.keys : function(object) {
            var keys = [],
                    property;

            for (property in object) {
                if (object.hasOwnProperty(property)) {
                    keys.push(property);
                }
            }

            return keys;
        },
        eachFrom = function (object, fromKey, fn, scope) {
            var keys = getKeys(object),
                start = keys.indexOf(fromKey),
                i,
                len;

            if (-1 !== start) {
                len = keys.length;
                for (i = start; i < len; i++) {
                    if (fn.call(scope || object, keys[i], object[keys[i]], object) === false) {
                        return;
                    }
                }
            }
        };

    Object.prototype.getKeys = function () {
        return getKeys(this);
    };

    Object.prototype.eachFrom = function (fromKey, fn, scope) {
        return eachFrom(this, fromKey, fn, scope);
    };
})();

var testObj = {
    3: '1',
    1354: '2',
    23235: '3',
    23: '4',
    456: '5',
    36225: '6'
};

testObj.eachFrom('23', function (key, value) {
    console.log('%s => %s', key, value);
});