I have a page that dynamically updates a HighCharts graph from a multiselect dropdown.
<!DOCTYPE html>
<html>
<head>
<script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
<script src="https://code.highcharts.com/highcharts.js"></script>
<script src="https://code.highcharts.com/modules/series-label.js"></script>
<script src="https://code.highcharts.com/modules/exporting.js"></script>
<script src="https://code.highcharts.com/modules/export-data.js"></script>
</head>
<body>
<!-- FIELDS -->
<div id="fields">
<form method="post" action="">
<select id="f" name="f[]" multiple>
<option value="rss1" select>1RSS(dB)</option>
<option value="rss2">2RSS(dB)</option>
<option value="rqly">RQly(%)</option>
<option value="rsnr">RSNR(dB)</option>
</select>
</form>
</div>
<!-- GRAPH -->
<div id="graph">No selection</div>
<script>
var updateChart = function(json) {
// console.log(json)
var options = {
chart: {
renderTo: 'graph',
type: 'line',
zoomType: 'x'
},
title: { text: null },
plotOptions: {
series: {
label: {
connectorAllowed: false
},
pointStart: 0
}
},
series: []
}
options.series = json;
var chart = new Highcharts.Chart(options);
// update yaxis
for (i=0; i<json.length; i++) {
if(i==0) {
// it seems that a yAxis already exist when graph is initialized. Did not find a smarter way to destroy it...
chart.yAxis[0].update({ title: { text: json[i].name }});
} else {
chart.addAxis({ title: { text: json[i].name } });
}
}
}
$(document).ready(function() {
$('#f').change(function() {
var requestParams = { f: $('#f').val() };
$.post('analysisajax.php', requestParams, updateChart);
});
});
</script>
</body>
</html>
Now, my analysisajax.php file looks like this:
<?php
header("Content-type: text/json");
// Initialize the session
session_start();
// Include config file
require_once "config.php";
$jsonObject = array();
$yaxis = 0;
foreach($_POST["f"] as $v) {
$data = array();
$sql = "SELECT $v FROM log WHERE id_user = " . $_SESSION["id_user"];
$result = $link->query($sql);
while($row = $result->fetch_row()) {
$data[] = $row[0];
}
$jsonObject[] = array(
"name" => $v,
"data" => $data,
"yAxis"=>$yaxis
);
$yaxis++;
}
$myJSON = json_encode($jsonObject, JSON_NUMERIC_CHECK);
echo $myJSON;
// Close connection
mysqli_close($link);
?>
When I'm selecting 1 value from the form, the graph loads without problem, but as soon as more than 1 value is selected from the dropdown, the graph fails with the following trace:
highcharts.src.js:498 Uncaught Error: Highcharts error #18: www.highcharts.com/errors/18
at Object.a.error (highcharts.src.js:498)
at highcharts.src.js:32669
at Array.forEach (<anonymous>)
at r.<anonymous> (highcharts.src.js:32621)
at a.fireEvent (highcharts.src.js:2635)
at r.bindAxes (highcharts.src.js:32618)
at r.init (highcharts.src.js:32482)
at a.Chart.initSeries (highcharts.src.js:26913)
at highcharts.src.js:28765
at Array.forEach (<anonymous>)
I feel that the issue is coming from my dynamic construction of yAxis but can't find a way to make it work. Any idea? Thanks a lot.
I eventually made it work with the following solution:
In the analysisajax.php script, I no longer generate the yaxis. I only send name and data.
The code to generate the graph now looks like this:
var updateChart = function(json) {
//console.log(json)
var options = {
chart: {
renderTo: 'graph',
type: 'line',
zoomType: 'x'
},
title: { text: null },
yAxis:[],
legend: {
layout: 'vertical',
align: 'right',
verticalAlign: 'bottom'
},
plotOptions: {
series: {
label: {
connectorAllowed: false
},
pointStart: 0
}
},
series: [],
tooltip: { shared: true }
}
var chart = new Highcharts.Chart(options);
// update axis and series
for (i=0; i<json.length; i++) {
// add axis
chart.addAxis({ title: { text: json[i].name } });
// add serie
var a = chart.series.length;
var seriesOptions = {
name: json[i].name,
data: json[i].data,
yAxis: a
}
chart.addSeries(seriesOptions,true);
chart.options.series.push(seriesOptions);
}
}
$(document).ready(function() {
$('#f').change(function() {
var requestParams = { f: $('#f').val() };
$.post('analysisajax.php', requestParams, updateChart);
//return false;
});
});