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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.js"></script>
<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 + " – ");
});
</script>
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<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>
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Copyright © 2007 - 2013 IOLA and Ole Laursen
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