Export to Csv is not working in Tablefilter.js

Question

I'am currently using TableFilter.js for my table. What i'm trying to do is to implement Csv Export function. This is my code :

<script src="plugins/js/jquery.min.js"></script>
<script src="plugins/js/bootstrap.min.js"></script>
<script src="plugins/js/tableFilter.js"></script>
    
<button class="btn btn-md btn-success tip-bottom csv" title="Download CSV" id="" onclick="export_csv();"><i class="fa fa-file-excel-o fa-sm"></i> CSV</button>
    
    function export_csv() {
        var form = document.createElement("form");
        form.setAttribute("method", "post");    
        form.setAttribute("action", 'export_csv.php');
        //var tf;
        //var TableFilter = require('tablefilter');
                var hiddenField = document.createElement("input");
                hiddenField.setAttribute("type", "hidden");
                hiddenField.setAttribute("name", "Header");
                hiddenField.setAttribute("value", tf.getHeadersText());
    
                form.appendChild(hiddenField);
             
                var hiddenField = document.createElement("input");
                hiddenField.setAttribute("type", "hidden");
                hiddenField.setAttribute("name", "String");
                hiddenField.setAttribute("value", tf.getFilteredValues());
    
                form.appendChild(hiddenField);
        
    
        document.body.appendChild(form);
        form.submit();
    }

export_csv.php

<?php
$string=$_POST['String'];
$header=$_POST['Header'];

$report= explode("," , $string); //place data into an array
$titles= explode("," , $header); //place column titles into an array

$cols= count($titles);
$fields= count($report);
$rows= $fields / ($cols+1); //cols+1 because there is an index column in data export

//start outputting CSV file
//write the title row

header("Content-type: text/csv");
header("Content-Disposition: attachment; filename=Monitoring.csv");

$p=0; //initial id of the record in the titles array

while ($p < $cols) {     //loop titles array and print it out
    echo "\"".$titles[$p]."\","; 
    $p++;
}
echo "\n"; //add a line break at the end of titles row

//now write the data rows

$p=0; //initial id of the record in the data array
$i=0; //current row in the data array

while ($i < $rows) { //loop every single row    
    $o=0; //initial id of the record in the data array, set to zero every new row
    $p++; //add 1 to skip the first index column in data array
    
    while ($o < $cols) { //loop data array until the end of the row and print it out
        echo "\"".$report[$p]."\",";
        $o++;
        $p++;   
    }
        
    echo "\n"; //add a line break at the end of data row
    $i++;
}
?>

table configuration

var tfConfig = {
        base_path: 'plugins/js/',
        col_0: 'none',
        col_1: 'select',
        col_3: 'select',
        col_4: 'select',
        col_5: 'select',
        col_6: 'select',
        col_7: 'select',
        col_8: 'select',
        col_9: 'select',
        col_10: 'select',
        col_11: 'select',
        col_12: 'select',
        col_13: 'select',
        auto_filter: { delay: 0 },
        watermark: ['','','control number','','','','','','','','','','',''],
        col_types: ['number', 'string', 'string', 'string', 'number', 'number', 'number', 'string', 'string', 'string','string','string','string'],
        columns_exact_match: [false,false,false,false,false,false,false,false,false,false,false,false,false,false], 
        // filters and headers position
        filters_row_index: 1, // UNDER TABLE HEADER
        headers_row_index: 0,
        highlight_keywords: true,
        no_results_message: true,
        alternate_rows: true,
        sticky_headers: true,
        rows_counter: true,
        //filters_cell_tag: "th",
        //enable_empty_option: true,
        loader: true,
        paging: {
          results_per_page: ['Records: ', [100, 200, 300, 5000]]
        },
        state: { 
            types: ['local_storage'],
            page_number: true,
            page_length: true,
            sort: true
        },
        extensions: [{ name: 'sort' }]
    };
    var tf = new TableFilter('table', tfConfig, 1);
    tf.init();

But it gives an error

tf is no defined

I don't know its cause, because I've already include tablefilter main js in my page.. And the tablefilter works in the table, just this export csv doesn't work.

Can someone help me? thanks