CSV to user custom report (Dygraph) - filereader

Question

I'm trying to create a good looking report from data which I get from Codesys PLC.
I'm going to create HTML page where you can put a file with data, and then it will be parsed into specific fields.
Codesys PLC writes CSV file of the following format:
under section some general data of the process
under trends which I going to visualize with Dygraph.
I tested Dygraph when CSV file consists only with GRAPH data (starts directly from captions row).
I created new dygraph and give it the CSV as File by FileReader.
Now I'm struggling how to hanle the section.
I can read it line by line, but then I need to hanle section as File again to put it into Dygraph.
So the main question is how to read a File as CSV file from specific position?
I tested some code, which I collects form some examples.
I'm sorry for that, I know it is not good but I'm a new with jscript and web programming.
But it works for Graph showing.
CSV File:
REPORT
StartDate, 2020/02/05 12:26:53
EndDateDate, 2020/02/06 12:26:53
Status, Finished
AverageTemperature, 123.45
AveragePressure, 0.0567
GRAPH
Time,Temperature,Pressure
2020/02/05 12:26:53,54.53312,0.5453312
2020/02/05 12:26:55,40.7445,0.1613245
2020/02/05 12:26:56,7.167816,0.03520107
2020/02/05 12:26:57,78.76286,0.03732681
2020/02/05 12:26:58,22.20001,0.06941796
2020/02/05 12:27:00,34.79605,0.7027158
<div id="graph"></div>
<input type="file" id="files" name="files[]" multiple />
<output id="list"></output>
<table id="outputTable">
</table>
<script>
var table = document.getElementById('outputTable');
function parseCSV(text, lineTerminator, cellTerminator) {
g = new Dygraph(
document.getElementById("graph"),
text,
{
series: {
'temperature': {
axis: 'y'
},
'pressure': {
axis: 'y2'
},
},
axes: {
y: {
labelsKMB: true,
independentTicks: true
},
y2: {
// set axis-related properties here
labelsKMB: true,
independentTicks: true
}
},
ylabel: 'Primary y-axis',
y2label: 'Secondary y-axis',
});
//break the lines apart
var lines = text.split(lineTerminator);
for(var j = 0; j<lines.length; j++){
if(lines[j] != ""){
//create a table row
var tableRow = table.appendChild(document.createElement('tr'));
//split the rows at the cellTerminator character
var information = lines[j].split(cellTerminator);
for(var k = 0; k < information.length; k++){
//append the cell to the row
var cell = tableRow.appendChild(document.createElement('td'));
cell.appendChild(document.createTextNode(information[k]));
}
}
}
}
function handleFileSelect(evt) {
var files = evt.target.files; // FileList object
// Loop through the FileList and populate the 'outputTable' with the data
for (var i = 0, f; f = files[i]; i++) {
var reader = new FileReader();
// Closure to capture the file information.
reader.onload = (function(theFile) {
return function(e) {
//call the parse function with the proper line terminator and cell terminator
parseCSV(e.target.result, '\n', ';');
};
})(f);
// Read the file as text
reader.readAsText(f);
}
}
document.getElementById('files').addEventListener('change', handleFileSelect, false);
</script>