Export chart to image silently

by nguyendong6789

HTML

<script type="text/javascript" src="http://www.amcharts.com/lib/3/amcharts.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/serial.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/exporting/amexport_combined.js"></script>
<div id="chartdiv"></div>
<div id="results"></div>

CSS

#chartdiv {
	width		: 100%;
	height		: 435px;
	font-size	: 11px;
}

JavaScript

var chart = AmCharts.makeChart("chartdiv", {
    "theme": "none",
    "type": "serial",
    "dataProvider": [{
        "country": "USA",
        "year2004": 3.5,
        "year2005": 4.2
    }, {
        "country": "UK",
        "year2004": 1.7,
        "year2005": 3.1
    }, {
        "country": "Canada",
        "year2004": 2.8,
        "year2005": 2.9
    }, {
        "country": "Japan",
        "year2004": 2.6,
        "year2005": 2.3
    }, {
        "country": "France",
        "year2004": 1.4,
        "year2005": 2.1
    }, {
        "country": "Brazil",
        "year2004": 2.6,
        "year2005": 4.9
    }, {
        "country": "Russia",
        "year2004": 6.4,
        "year2005": 7.2
    }, {
        "country": "India",
        "year2004": 8,
        "year2005": 7.1
    }, {
        "country": "China",
        "year2004": 9.9,
        "year2005": 10.1
    }],
    "valueAxes": [{
        "stackType": "3d",
        "unit": "%",
        "position": "left",
        "title": "GDP growth rate",
    }],
    "startDuration": 1,
    "graphs": [{
        "balloonText": "GDP grow in [[category]] (2004): <b>[[value]]</b>",
        "fillAlphas": 0.9,
        "lineAlpha": 0.2,
        "title": "2004",
        "type": "column",
        "valueField": "year2004"
    }, {
        "balloonText": "GDP grow in [[category]] (2005): <b>[[value]]</b>",
        "fillAlphas": 0.9,
        "lineAlpha": 0.2,
        "title": "2005",
        "type": "column",
        "valueField": "year2005"
    }],
    "plotAreaFillAlphas": 0.1,
    "depth3D": 60,
    "angle": 30,
    "categoryField": "country",
    "categoryAxis": {
        "gridPosition": "start"
    }
});
chart.addListener("rendered",function(e) {
    setTimeout(function() {
        var ame = new AmCharts.AmExport(e.chart,{},true);
        ame.output({
            format: "png",
            
        },function(datastring) {
            var img = document.createElement("img");
            img.src = datastring;
            
     ...