[рони]

zharinov,

// первый
    var clbk = document.querySelector('.js-callback');
    //второй
    var clbk2 = document.querySelector('.js-callback2');
    var initClbk = new Powerange(clbk, { callback: displayValue, start: 405000, max: 500000 });

    function displayValue() {
    document.getElementById('js-display-callback').innerHTML = clbk.value;
    var cl = clbk.value*clbk2.value;
    document.getElementById('clientov').innerHTML = cl;
       }



    var initClbk2 = new Powerange(clbk2, { callback: displayValue2, start: 17, max: 30, step: 1 });

    function displayValue2() {
      document.getElementById('js-display-callback2').innerHTML = clbk2.value;

    var cl = clbk.value*clbk2.value;
    document.getElementById('clientov').innerHTML = cl;


}
  //третий
    var clbk3 = document.querySelector('.js-callback3');
    var initClbk3 = new Powerange(clbk3, { callback: displayValue3, start: 3650, max: 5000 });

    function displayValue3() {
      document.getElementById('js-display-callback3').innerHTML = clbk3.value;



}