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<head>

	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">

	<title>Flot Examples: Tracking</title>

	<link href="../examples.css" rel="stylesheet" type="text/css">

	<!--[if lte IE 8]><script language="javascript" type="text/javascript" src="../../excanvas.min.js"></script><![endif]-->

	<script language="javascript" type="text/javascript" src="../../jquery.js"></script>

	<script language="javascript" type="text/javascript" src="../../jquery.flot.js"></script>

	<script language="javascript" type="text/javascript" src="../../jquery.flot.crosshair.js"></script>

	<script type="text/javascript">



	$(function() {



		var sin = [], cos = [];

		for (var i = 0; i < 14; i += 0.1) {

			sin.push([i, Math.sin(i)]);

			cos.push([i, Math.cos(i)]);

		}



		plot = $.plot("#placeholder", [

			{ data: sin, label: "sin(x) = -0.00"},

			{ data: cos, label: "cos(x) = -0.00" }

		], {

			series: {

				lines: {

					show: true

				}

			},

			crosshair: {

				mode: "x"

			},

			grid: {

				hoverable: true,

				autoHighlight: false

			},

			yaxis: {

				min: -1.2,

				max: 1.2

			}

		});



		var legends = $("#placeholder .legendLabel");



		legends.each(function () {

			// fix the widths so they don't jump around

			$(this).css('width', $(this).width());

		});



		var updateLegendTimeout = null;

		var latestPosition = null;



		function updateLegend() {



			updateLegendTimeout = null;



			var pos = latestPosition;



			var axes = plot.getAxes();

			if (pos.x < axes.xaxis.min || pos.x > axes.xaxis.max ||

				pos.y < axes.yaxis.min || pos.y > axes.yaxis.max) {

				return;

			}



			var i, j, dataset = plot.getData();

			for (i = 0; i < dataset.length; ++i) {



				var series = dataset[i];



				// Find the nearest points, x-wise



				for (j = 0; j < series.data.length; ++j) {

					if (series.data[j][0] > pos.x) {

						break;

					}

				}



				// Now Interpolate



				var y,

					p1 = series.data[j - 1],

					p2 = series.data[j];



				if (p1 == null) {

					y = p2[1];

				} else if (p2 == null) {

					y = p1[1];

				} else {

					y = p1[1] + (p2[1] - p1[1]) * (pos.x - p1[0]) / (p2[0] - p1[0]);

				}



				legends.eq(i).text(series.label.replace(/=.*/, "= " + y.toFixed(2)));

			}

		}



		$("#placeholder").bind("plothover",  function (event, pos, item) {

			latestPosition = pos;

			if (!updateLegendTimeout) {

				updateLegendTimeout = setTimeout(updateLegend, 50);

			}

		});



		// Add the Flot version string to the footer



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

	});



	</script>

</head>

<body>



	<div id="header">

		<h2>Tracking</h2>

	</div>



	<div id="content">



		<div class="demo-container">

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

		</div>



		<p>You can add crosshairs that'll track the mouse position, either on both axes or as here on only one.</p>



		<p>If you combine it with listening on hover events, you can use it to track the intersection on the curves by interpolating the data points (look at the legend).</p>



		<p id="hoverdata"></p>



	</div>



	<div id="footer">

		Copyright &copy; 2007 - 2014 IOLA and Ole Laursen

	</div>



</body>

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