[danik.js]

koeshiro, ты о чем вобще?

var data = [{
	url: 'http://site.ru',
	title: 'title',
	num: 1
}];
localStorage.setItem('Nf',JSON.stringify(data));

var data = JSON.parse(localStorage.getItem('Nf'));
data.push({
	url: 'http://site2.ru',
	title: 'title2',
	num: 2
});
localStorage.setItem('Nf',JSON.stringify(data));

var data = JSON.parse(localStorage.getItem('Nf'));

alert(data.map(function(item){
	return '{' + Object.keys(item).map(function(key){ return key + ':' + item[key]}) + '}';
}));