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December 21, 2018 at 3:18 am #23818

gereby

I have a somewhat similiar case. I want to create a dynamic Chart from an Mysql-DB

Unfortunatelly, I get the Msg “TypeError: chart is undefined”
I am “only” a Graphic Designer and no programmer :()

=============================================================================================================
SCRIPT
=============================================================================================================

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title></title>
    <script src="https://code.jquery.com/jquery-3.3.1.js" integrity="sha256-2Kok7MbOyxpgUVvAk/HJ2jigOSYS2auK4Pfzbm7uH60=" crossorigin="anonymous"></script>
    <script src="https://cdn.canvasjs.com/canvasjs.min.js"></script>

  <script type="text/javascript">
	var updateInterval = 100;
	var chart;
	var dps;
	$(document).ready(function () {

		$.getJSON("testdata.php", function (result) {
			dps = result;
			var chart = new CanvasJS.Chart("chartContainer", {
				title:{
					text: "Test",
				},
				axisY:{
					minimum: 0,
					maximum: 1000
				},
				data: [
					{
						type: "stackedBar",
						dataPoints: dps
					}
				]
			});
			
		chart.render();
	});

var updateChart = function () {
	$.getJSON("testdata.php", function (result) {
		dps.splice(0, dps.length);
		$.each(result, function (index, value) {
			dps.push(value);
		});
	});

chart.render();
};

setInterval(function(){updateChart()}, updateInterval);

});

</script> 
</head>
<body>
BODY
    <div id="chartContainer" style="width: 800px; height: 380px;"></div>

</body>
</html>

=============================================================================================================
DATA
=============================================================================================================

<?php

header('Content-Type: application/json');

$con = mysqli_connect("localhost","wp1","QPZBtAe7","wp1");

// Check connection
if (mysqli_connect_errno($con))
{
    echo "Failed to connect to DataBase: " . mysqli_connect_error();
}else
{
    $data_points = array();
    
    $result = mysqli_query($con, "SELECT id,Laserschneider_Druckluft_Volumenstrom_Nm3h FROM blb ORDER BY id DESC LIMIT 500");
    
    while($row = mysqli_fetch_array($result))
    {        
        $point = array("label" => $row['id'] , "y" => $row['Laserschneider_Druckluft_Volumenstrom_Nm3h']);
        array_push($data_points, $point);        
    }
    
    echo json_encode($data_points, JSON_NUMERIC_CHECK);
}
mysqli_close($con);