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<title>Flot Examples: AJAX</title>
<link href="../examples.css" rel="stylesheet" type="text/css">
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<script language="javascript" type="text/javascript" src="../../jquery.flot.js"></script>
<script type="text/javascript">

$(function() {

        var options = {
                lines: {
                        show: true
                },
                points: {
                        show: true
                },
                xaxis: {
                        tickDecimals: 0,
                        tickSize: 1
                }
        };

        var data = [];

        $.plot("#placeholder", data, options);

        // Fetch one series, adding to what we already have

        var alreadyFetched = {};

        $("button.fetchSeries").click(function () {

                var button = $(this);

                // Find the URL in the link right next to us, then fetch the data

                var dataurl = button.siblings("a").attr("href");

                function onDataReceived(series) {

                        // Extract the first coordinate pair; jQuery has parsed it, so
                        // the data is now just an ordinary JavaScript object

                        var firstcoordinate = "(" + series.data[0][0] + ", " + series.data[0][1] + ")";
                        button.siblings("span").text("Fetched " + series.label + ", first point: " + firstcoordinate);

                        // Push the new data onto our existing data array

                        if (!alreadyFetched[series.label]) {
                                alreadyFetched[series.label] = true;
                                data.push(series);
                        }

                        $.plot("#placeholder", data, options);
                }

                $.ajax({
                        url: dataurl,
                        type: "GET",
                        dataType: "json",
                        success: onDataReceived
                });
        });

        // Initiate a recurring data update

        $("button.dataUpdate").click(function () {

                data = [];
                alreadyFetched = {};

                $.plot("#placeholder", data, options);

                var iteration = 0;

                function fetchData() {

                        ++iteration;

                        function onDataReceived(series) {

                                // Load all the data in one pass; if we only got partial
                                // data we could merge it with what we already have.

                                data = [ series ];
                                $.plot("#placeholder", data, options);
                        }

                        // Normally we call the same URL - a script connected to a
                        // database - but in this case we only have static example
                        // files, so we need to modify the URL.

                        $.ajax({
                                url: "data-eu-gdp-growth-" + iteration + ".json",
                                type: "GET",
                                dataType: "json",
                                success: onDataReceived
                        });

                        if (iteration < 5) {
                                setTimeout(fetchData, 1000);
                        } else {
                                data = [];
                                alreadyFetched = {};
                        }
                }

                setTimeout(fetchData, 1000);
        });

        // Load the first series by default, so we don't have an empty plot

        $("button.fetchSeries:first").click();

        // Add the Flot version string to the footer

        $("#footer").prepend("Flot " + $.plot.version + " &ndash; ");
});

</script>

</head> <body>

<div id="header">
        <h2>AJAX</h2>
</div>

<div id="content">

        <div class="demo-container">
                <div id="placeholder" class="demo-placeholder"></div>
        </div>

        <p>Example of loading data dynamically with AJAX. Percentage change in GDP (source: <a href="http://epp.eurostat.ec.europa.eu/tgm/table.do?tab=table&init=1&plugin=1&language=en&pcode=tsieb020">Eurostat</a>). Click the buttons below:</p>

        <p>The data is fetched over HTTP, in this case directly from text files. Usually the URL would point to some web server handler (e.g. a PHP page or Java/.NET/Python/Ruby on Rails handler) that extracts it from a database and serializes it to JSON.</p>

        <p>
                <button class="fetchSeries">First dataset</button>
                [ <a href="data-eu-gdp-growth.json">see data</a> ]
                <span></span>
        </p>

        <p>
                <button class="fetchSeries">Second dataset</button>
                [ <a href="data-japan-gdp-growth.json">see data</a> ]
                <span></span>
        </p>

        <p>
                <button class="fetchSeries">Third dataset</button>
                [ <a href="data-usa-gdp-growth.json">see data</a> ]
                <span></span>
        </p>

        <p>If you combine AJAX with setTimeout, you can poll the server for new data.</p>

        <p>
                <button class="dataUpdate">Poll for data</button>
        </p>

</div>

<div id="footer">
        Copyright &copy; 2007 - 2014 IOLA and Ole Laursen
</div>

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