1var json = [
2    {"text":"menu1","parent":"#","id":"128102"},
3    {"text":"menu1.1","parent":"128102","id":"128103"},
4    {"text":"menu1.1","parent":"128102","id":"128103"}
5];
6
7var ids = [];
8var clean = [];
9
10$.each(json, function(index, value) {
11    if($.inArray(value.id, ids) == -1)
12    {
13        ids.push(value.id);
14        clean.push(value);
15    }
16});