javascript - jQuery $.getJSON throws Unexpected Token

I'm a JavaScript beginner. I want to retrieve some data from Steam Market using the following URL:

https://steamcommunity.com/market/priceoverview/?country=PL¤cy=3&appid=730&callback=?&market_hash_name=Operation%20Vanguard%20Weapon%20Case#

I get this response in my browser:

{"success":true,"lowest_price":"0,09\u20ac","volume":"1,017","median_price":"0,10\u20ac"}

But I can't get it to work in JS.

var amount = prompt("How many cases do you have?\t");
$.getJSON("http://steamcommunity.com/market/priceoverview/?country=PL¤cy=3&appid=730&callback=?&market_hash_name=Operation%20Vanguard%20Weapon%20Case#",

    function(json) {
    var raw_price = json.lowest_price;
    var price = raw_price.split('&')[0];
    var price_total = price*parseInt(amount);
    alert(price_total + '€');
});

It just throws me:

Uncaught SyntaxError: Unexpected token :

What's wrong with this code?

Answer

The problem has been eventually solved by me. The issue was that Steam didn't allow to access their market data using a JavaScript code in a browser because of Access-Control-Allow-Origin.

I have rewritten my JS code to PHP and sent the same request, but this time from my own WWW server:

function get_price() {
    $url = "https://steamcommunity.com/market/priceoverview/?country=PL¤cy=3&appid=730&callback=?&market_hash_name=Operation%20Vanguard%20Weapon%20Case";
    $json = file_get_contents($url);
    $price = json_decode($json);
    $price_case = $price->{"lowest_price"};
    return number_format($price_case, 2);
}

Worked like a charm.