1You are calling:
2
3JSON.parse(scatterSeries)
4But when you defined scatterSeries, you said:
5
6var scatterSeries = []; 
7When you try to parse it as JSON it is converted to a string (""), which is empty, so you reach the end of the string before having any of the possible content of a JSON text.
8
9scatterSeries is not JSON. Do not try to parse it as JSON.
10
11data is not JSON either (getJSON will parse it as JSON automatically).
12
13ch is JSON … but shouldn't be. You should just create a plain object in the first place:
14
15var ch = {
16    "name": "graphe1",
17    "items": data.results[1]
18};
19
20scatterSeries.push(ch);
21In short, for what you are doing, you shouldn't have JSON.parse anywhere in your code. The only place it should be is in the jQuery library itself