var smallest = '';
var largest = '';

Object.keys(document).forEach(function(key){
    if (key.length < smallest.length){
        smallest = key;
    } else if(key.length > largest.length) {
        largest = key;
    }
});

Object.keys(window).forEach(function(key){
    if (key.length < smallest.length){
        smallest = key;
    } else if(key.length > largest.length) {
        largest = key;
    }
});

Object.keys(navigator).forEach(function(key){
    if (key.length < smallest.length){
        smallest = key;
    } else if(key.length > largest.length) {
        largest = key;
    }
});
console.log(smallest);
console.log(largest);