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<title>Flot Examples</title>
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<h1>Flot Examples</h1>
<div id="placeholder" style="width:600px;height:300px;"></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>
<input class="fetchSeries" type="button" value="First dataset"> -
<a href="data-eu-gdp-growth.json">data</a> -
<span></span>
</p>
<p>
<input class="fetchSeries" type="button" value="Second dataset"> -
<a href="data-japan-gdp-growth.json">data</a> -
<span></span>
</p>
<p>
<input class="fetchSeries" type="button" value="Third dataset"> -
<a href="data-usa-gdp-growth.json">data</a> -
<span></span>
</p>
<p>If you combine AJAX with setTimeout, you can poll the server
for new data.</p>
<p>
<input class="dataUpdate" type="button" value="Poll for data">
</p>
<script type="text/javascript">
$(function () {
var options = {
lines: { show: true },
points: { show: true },
xaxis: { tickDecimals: 0, tickSize: 1 }
};
var data = [];
var placeholder = $("#placeholder");
$.plot(placeholder, data, options);
// fetch one series, adding to what we got
var alreadyFetched = {};
$("input.fetchSeries").click(function () {
var button = $(this);
// find the URL in the link right next to us
var dataurl = button.siblings('a').attr('href');
// then fetch the data with jQuery
function onDataReceived(series) {
// extract the first coordinate pair so you can see that
// data is now an ordinary Javascript object
var firstcoordinate = '(' + series.data[0][0] + ', ' + series.data[0][1] + ')';
button.siblings('span').text('Fetched ' + series.label + ', first point: ' + firstcoordinate);
// let's add it to our current data
if (!alreadyFetched[series.label]) {
alreadyFetched[series.label] = true;
data.push(series);
}
// and plot all we got
$.plot(placeholder, data, options);
}
$.ajax({
url: dataurl,
method: 'GET',
dataType: 'json',
success: onDataReceived
});
});
// initiate a recurring data update
$("input.dataUpdate").click(function () {
// reset data
data = [];
alreadyFetched = {};
$.plot(placeholder, data, options);
var iteration = 0;
function fetchData() {
++iteration;
function onDataReceived(series) {
// we get all the data in one go, if we only got partial
// data, we could merge it with what we already got
data = [ series ];
$.plot($("#placeholder"), data, options);
}
$.ajax({
// usually, we'll just 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
url: "data-eu-gdp-growth-" + iteration + ".json",
method: 'GET',
dataType: 'json',
success: onDataReceived
});
if (iteration < 5)
setTimeout(fetchData, 1000);
else {
data = [];
alreadyFetched = {};
}
}
setTimeout(fetchData, 1000);
});
});
</script>
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