python:


@app.route('/task_status', methods=['POST'])
def check_task_status():
    print(f'str(request.json data form server) - {str(request.json)}')


js:


    (function ($) {
    $(document).ready(function () {
        let job_id = {"job_id": getUrlParameter('task')};
        JSON.stringify(job_id);
        console.log(job_id);
        let SetIntervalId = setInterval(function () {$.ajax(
            {
                type: 'POST',
                url: '/task_status',
                data: JSON.stringify(job_id),
                dataType: "json",
                success: function (response) {
                    if (response['status'] === 'SUCCESS') {
                        $("#download_btn").prop("disabled", false);
                        clearInterval(SetIntervalId);
                    } else if (response['status'] === 'FAILURE') {
                        clearInterval(SetIntervalId);
                        alert('Task is failed!')
                    } else {
                    }
                }
            })
        }, 1000);