Zing Feed get data from rest api

I am getting a json data from rest api and i want to use it as input to ZingFeed.

<!DOCTYPE html>
<html>

<head>
    <meta charset="ISO-8859-1">
    <title>Insert title here</title>
    <script src='http://cdn.zingchart.com/zingchart.min.js'></script>
   <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script>
</head>

<body>
    <script>
    function getNewData()
    {
        $.ajax({ 
            type: "GET",
            dataType: "json",
            headers: {
                Accept:"application/json",
                "Access-Control-Allow-Origin": "*"
            },
            url: "/PerformanceMonitor/showProcessUsage/chrome",
            success: function(data){ 
                var mem = data.mem.size/10000;
                 return mem/10000;
                //$("#processInfo").append(data.mem.size);
                //$("#processInfo").append("   ")

            }
        });
        //return parseInt(memSize);
    }

    var chartData = {
        "type":"line",
        "refresh": {
            "type": "feed",
            "transport": "js",
            "url": "feed()",
            "interval": 200
        },
        "series":[
            {
                "values":[]
            }
        ]
    };


    window.onload = function() {
        zingchart.render({
            id: "chartDiv",
            data: chartData,
            height: 600,
            width: "100%"
        });
    };

    window.feed = function(callback) {
        var tick = {};
       // tick.plot0 = parseInt(10 + 900 * Math.random(), 10);
       tick.plot0 = parseInt(getNewData());
        //tick.plot0 = parseInt(1);
        callback(JSON.stringify(tick));
    };
    </script>
    <div id="processInfo"></div>
    <div id='chartDiv'></div>

</body>

</html>

It is working fine when seen in firebug.The data (i.e mem in this case is really huge, so i have divided it twice before assigning it to tick.plot0). After getting assigned to tick.plot0 .. it shows Nan when hovered over in the developer tools. Could you help me plotting these huge values in ZingFeed Charts

Thanks in advance

The issue here is the nature of asynchronous functions in Javascript. Returning the data from AJAX doesn't work the way you've attempted above. You can read more about it here.

Here's a working solution.

I work on the ZingChart team. Let me know if you have other questions about the ZingChart library.

<!DOCTYPE html>
<html>

<head>
    <meta charset="ISO-8859-1">
    <title>Insert title here</title>
    <script src='http://cdn.zingchart.com/zingchart.min.js'></script>
   <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script>
</head>

<body>
    <script>
    var chartData = {
        "type":"line",
        "refresh": {
            "type": "feed",
            "transport": "js",
            "url": "feed()",
            "interval": 200
        },
        "series":[
            {
                "values":[]
            }
        ]
    };

    window.onload = function() {
        zingchart.render({
            id: "chartDiv",
            data: chartData,
            height: 600,
            width: "100%"
        });
    };

    window.feed = function(callback) {
        $.ajax({
            type: "GET",
            dataType: "json",
            headers: {
                Accept: "application/json",
                "Access-Control-Allow-Origin": "*"
            },
            url: "/PerformanceMonitor/showProcessUsage/chrome",
            success: function (data) {
                var mem = data.mem.size/10000;
                var tick = {
                    plot0: parseInt(mem)
                };
                callback(JSON.stringify(tick));
            }
        });
    };
    </script>
    <div id="processInfo"></div>
    <div id='chartDiv'></div>

</body>